A hooking path planning method and system for a folding arm type pull arm frame of a garbage truck

Abstract

A hooking path planning method and system for a folding arm type pull arm frame of a garbage truck, in the method, based on garbage bin center of gravity offset and vehicle inclination angle data, an initial joint trajectory satisfying end constraint is generated combined with a kinematics model; then, a load torque sequence of each folding arm is calculated using a dynamics model, a trajectory segment with torque mutation and a target folding arm are identified, and a target compensation torque required to eliminate the mutation is calculated; then, under the premise of keeping the end hooking space trajectory unchanged, the joint compensation amount of other collaborative folding arms is calculated using the redundancy freedom of the multi-section folding arm; finally, the compensation amount is fused into the initial trajectory to reconstruct the target smooth hooking path, and control instructions are output to the hydraulic cylinder according to the target smooth hooking path, so that the smooth and safe hooking operation is realized. The application is used for suppressing mechanical shaking of the pull arm frame under complex stress state, and improving the position control precision and stability of the lifting operation of the heavy load garbage bin hooking butt joint.

Description

Technical Field

[0001] This application belongs to the field of process control, and in particular relates to a hook path planning method and system for a folding boom arm of a garbage truck. Background Technology

[0002] With the acceleration of urbanization, garbage transfer equipment plays a vital role in maintaining urban environmental sanitation. Traditional garbage truck boom lifts typically require significant overhead space for hooking and hoisting garbage containers. In space-constrained work areas, traditional boom lifts are prone to spatial interference due to their excessive lifting height, thus reducing the applicability of garbage collection equipment.

[0003] To address the aforementioned space constraints, a control method for a multi-section folding boom lift has been proposed. This technology incorporates a folding right-angle boom, a folding main boom, and a lifting boom within the boom lift, each driven by multiple hydraulic cylinders. During hooking operations, the technology sequentially controls the extension and retraction of each hydraulic cylinder according to a pre-set multi-stage folding trajectory, enabling the boom lift to hook and lift the garbage container while in its folded state. This reduces the overall height of the boom lift during operation, improving the operational flexibility of garbage trucks in low-ceilinged spaces such as basements.

[0004] However, in the underground parking garages of supermarkets, garbage bins are typically filled with dense kitchen waste or construction debris, and the ground they are placed on often has a certain slope or unevenness, resulting in an uneven distribution of the bin's center of gravity and an initial tilted posture. When related technologies control multi-section folding arms to perform heavy-load hooking and lifting in this scenario according to a preset folding motion trajectory, the load torque borne by each section of the folding arm will dynamically change at different stages of movement due to the shift in the garbage bin's center of gravity and the additional resistance from the ground slope. This causes pressure fluctuations in each hydraulic cylinder when dealing with sudden changes in load torque. Such pressure fluctuations in the hydraulic system will cause unstable output power of the multi-section folding arms during coordinated movement, which in turn will cause mechanical vibration of the boom when hooking and lifting heavy-load garbage bins, reducing the positional control accuracy of the boom hook and the bin hook center, and also reducing the stability of the entire lifting operation. Summary of the Invention

[0005] This application provides a hooking path planning method and system for a folding boom type garbage truck, which is used to suppress the mechanical vibration of the boom under complex stress conditions, and improve the position control accuracy of hooking and docking of heavy-duty garbage containers and the stability of hoisting operations.

[0006] In the first aspect, this application provides a hooking path planning method for a folding arm type hook arm of a garbage truck, which obtains the center of gravity offset data of the target garbage container and the current vehicle attitude tilt angle data, and combines the preset hook arm kinematic model to generate an initial joint motion trajectory that satisfies the end hooking position constraint.

[0007] Based on the initial hook trajectory and the preset boom dynamic model, calculate the load torque sequence of each folding boom under the initial hook trajectory;

[0008] Traverse the load torque sequence, identify the trajectory segments where the torque change rate is greater than the preset torque change rate threshold as abrupt trajectory segments, and extract the target folding arm that generates torque abrupt changes within the abrupt trajectory segments;

[0009] Calculate the target compensation torque required for the target folding arm to eliminate torque abrupt changes within the abrupt trajectory segment;

[0010] Under the constraint of keeping the spatial trajectory of the hook at the end of the boom unchanged, based on the target compensation torque and the preset boom dynamics model, the joint compensation of other folding arms that move in coordination with the target folding arm is calculated using the redundant degrees of freedom of the multi-section folding arm.

[0011] The joint compensation amount is integrated into the initial joint motion trajectory of each folding arm in the abrupt trajectory segment to reconstruct the target smooth hooking path.

[0012] Control commands are output to each hydraulic cylinder according to the target hooking path.

[0013] By employing the aforementioned technical solution, an initial joint motion trajectory is generated by acquiring data on the garbage container's center of gravity shift and vehicle attitude tilt angle. Combined with a dynamic model to calculate the load torque sequence, this allows for precise location of abrupt trajectory segments where the torque change rate exceeds a threshold, as well as the target folding arm. Based on this, the compensation torque required to eliminate torque abrupt changes is calculated. The redundant degrees of freedom of the multi-section folding arm are used to determine the joint compensation amount of other cooperating folding arms, which is then integrated into the initial trajectory. This process, while strictly maintaining the hook trajectory at the end of the boom, shares the transient overload torque of the target folding arm through the cooperative movement of other folding arms, reducing the mechanical impact on the hydraulic system caused by local torque abrupt changes due to garbage container eccentricity or vehicle tilt. This solution smooths the force fluctuations of each joint, improving the stability and safety of the boom during hooking operations under complex conditions. This suppresses mechanical vibrations generated by the boom under complex stress states, enhancing the position control accuracy and lifting stability of the heavy-duty garbage container hooking and docking.

[0014] In conjunction with some implementations of the first aspect, in some implementations, under the constraint of keeping the spatial trajectory of the hook at the end of the boom unchanged, based on the target compensation torque and the preset boom dynamics model, the joint compensation of other folding arms that move in coordination with the target folding arm is calculated using the redundant degrees of freedom of the multi-section folding arm. Specifically, this includes:

[0015] Based on the preset boom dynamics model, the redundant motion space that other folding arms can perform is extracted without changing the spatial trajectory of the hook at the end of the boom.

[0016] Obtain the dynamic load margin of other folding arms in the current motion posture. The dynamic load margin is used to characterize the safety threshold that each other folding arm can withstand additional torque without overload.

[0017] Based on the dynamic load margin, the target compensation torque is weighted and distributed within the redundant motion space to obtain the equivalent compensation torque shared by each of the other folding arms.

[0018] Based on the equivalent compensation torque and the preset boom dynamic model, the joint compensation amount of other folding arms is obtained by reverse calculation.

[0019] By adopting the above technical solution, when calculating joint compensation using redundant degrees of freedom, the redundant motion space that does not change the end-effector trajectory is extracted, and the dynamic load margin that prevents overload of other folding arms in the current posture is obtained. The target compensation torque is then weighted according to this load margin. This allocation mechanism fully considers the actual load-bearing capacity of each cooperating folding arm, avoiding the risk of secondary overload of other folding arms due to blindly transferring the compensation torque. The joint compensation is then calculated in reverse based on the allocated equivalent compensation torque, making the torque distribution of the entire multi-section folding arm system more balanced and reasonable. This solution, while achieving torque compensation, ensures that each folding arm is within the safe stress threshold range to the greatest extent, further improving the structural safety and overall operational reliability of the boom system during dynamic compensation.

[0020] In conjunction with some implementations of the first aspect, in some implementations, the joint compensation amount is integrated into the initial joint motion trajectory of each folding arm within the abrupt trajectory segment to reconstruct the target smooth hooking path, specifically including:

[0021] Determine the entry and exit nodes of the mutation trajectory segment in the initial joint motion trajectory, and extract the initial motion state data of the initial joint motion trajectory at the entry and exit nodes;

[0022] Based on the initial motion state data, construct a smooth transition function that matches both ends of the abrupt trajectory segment;

[0023] The joint compensation amount is modulated in the time domain using a smooth transition function to obtain the modulated target joint compensation amount, so that the value and rate of change of the target joint compensation amount at the cut-in node and the cut-out node both approach zero.

[0024] The target joint compensation amount is superimposed onto the initial joint motion trajectory of each folding arm within the abrupt trajectory segment to reconstruct the target smooth hooking path.

[0025] By employing the above technical solution, during the process of fusing the joint compensation amount into the initial trajectory, a smooth transition function matching both ends is constructed by determining the entry and exit nodes of the abrupt trajectory segment and extracting the initial motion state data. This function is then used to temporally modulate the joint compensation amount, forcing the value and rate of change of the target joint compensation amount to approach zero at the entry and exit nodes, before it is superimposed onto the initial trajectory. This processing method ensures the continuity of position and velocity between the compensated trajectory and the original trajectory at the splicing nodes, eliminating kinematic abrupt changes that may be caused by directly superimposing the compensation amount. This solution effectively reduces the secondary dynamic impact on the hydraulic actuator at the moment of compensation intervention and withdrawal, and improves the smoothness of the folding arm's motion when switching between the entire abrupt trajectory segment.

[0026] In conjunction with some embodiments of the first aspect, in some embodiments, after outputting control commands to each hydraulic cylinder according to the target smooth hooking path, the method further includes:

[0027] Obtain the real-time working pressure of each hydraulic cylinder when performing joint compensation;

[0028] If the real-time working pressure of the target hydraulic cylinder is continuously greater than the preset pressure threshold, it is determined that the garbage container has a large static off-center load.

[0029] Under the constraint of keeping the current spatial position of the end hook point of the boom unchanged, control the multi-section folding boom to perform redundant attitude adjustment until the joint corresponding to the target hydraulic cylinder moves to the preset mechanical dead point position or the preset structural limit point.

[0030] Lock the hydraulic circuit of the target hydraulic cylinder, so that the joint corresponding to the target hydraulic cylinder is switched from hydraulic drive to mechanical rigid support;

[0031] In the preset boom kinematic model, the joint degrees of freedom corresponding to the target hydraulic cylinder are deleted, and the remaining unlocked joints are used to regenerate the control commands to maintain the target's stable hooking path.

[0032] By adopting the above technical solution, and through real-time monitoring of the hydraulic cylinder's working pressure, when it is identified that the target hydraulic cylinder pressure is continuously exceeding the limit due to a large static off-center load, the folding arm is controlled to perform redundant posture adjustments while maintaining the constraint of the end hook point unchanged. This allows the target joint to move to the mechanical dead point or structural limit point and lock its hydraulic circuit. This mechanism switches the force mode of the target joint from hydraulic active drive to mechanical rigid support, directly bearing the extreme destructive force generated by the large off-center load using the physical limit of the metal structure. Subsequently, the joint is removed from the kinematic model, and control commands are regenerated using the remaining unlocked joints, enabling the system to maintain the predetermined hooking path even under extreme conditions where some joints are passively locked. This solution effectively reduces the risk of the target hydraulic cylinder being in a high-pressure overflow state for a long time under severe off-center load, reduces the probability of damage to hydraulic components, and significantly improves the ultimate load-bearing capacity and operational fault tolerance of the boom system in the face of extreme and harsh working conditions.

[0033] In conjunction with some implementations of the first aspect, in some implementations, under the constraint of keeping the current spatial position of the end hook point of the boom unchanged, the multi-section folding boom is controlled to perform redundant posture adjustments until the joint corresponding to the target hydraulic cylinder moves to a preset mechanical dead point position or a preset structural limit point, specifically including:

[0034] Set the target hydraulic cylinder as the master retraction actuator, and set the other hydraulic cylinders in the multi-section folding arm, excluding the target hydraulic cylinder, as the driven compensation actuators.

[0035] According to the preset safety step size, generate a fine-tuning displacement command that causes the main retraction actuator to move unidirectionally to the preset mechanical dead point position or the preset structural limit point.

[0036] Based on the preset boom kinematic model, the virtual offset vector of the end hook point deviating from the current spatial position is calculated when the main retraction actuator executes the fine-tuning displacement command alone;

[0037] With the goal of counteracting the virtual offset vector, synchronous compensation displacement commands corresponding to each driven compensation actuator are generated through inverse kinematics calculation.

[0038] The fine-tuning displacement command and the synchronous compensation displacement command are issued and executed synchronously as a linkage control cycle, and then the execution returns to set the target hydraulic cylinder as the main retraction actuator until the main retraction actuator reaches the preset mechanical dead point position or the preset structural limit point.

[0039] By adopting the above technical solution, the target hydraulic cylinder is set as the main retraction actuator and the remaining cylinders are set as driven compensation actuators. Fine-tuning displacement commands are generated according to a preset safety step size. The virtual offset vector of the end hook point caused by the individual action of the main retraction actuator is calculated. Then, a synchronous compensation displacement command to counteract this offset is generated through inverse kinematics calculation, and the two are synchronously issued and executed in a linked control cycle. This linked compensation mechanism allows other hydraulic cylinders to perform real-time and precise reverse motion compensation during the retraction of the target hydraulic cylinder towards the mechanical dead point or structural limit point. This strictly constrains the spatial displacement of the end hook point when dynamically adjusting the redundant posture of the folding arm. This solution effectively reduces the risk of accidental shaking or disengagement of the garbage container due to large-scale retraction by a single cylinder, and improves the operational stability and safety of the boom frame during posture reconstruction under extreme off-center load conditions.

[0040] In some embodiments, in conjunction with the first aspect, after regenerating control commands to maintain a stable hooking path for the target using the remaining unlocked joints, the method further includes:

[0041] Real-time monitoring of the equivalent load torque acting on the target hydraulic cylinder by the boom in the current spatial position;

[0042] When the equivalent load torque drops to the preset recovery threshold, the hydraulic circuit of the target hydraulic cylinder is switched to a floating state that allows passive displacement of the piston rod;

[0043] Based on the preset boom kinematic model, a dead-point disengagement command is issued to the remaining unlocked joints;

[0044] Control the remaining unlocked joints to execute the dead-point disengagement command to generate displacement, so as to drag the target hydraulic cylinder in the floating state away from the mechanical dead point through the linkage of the boom;

[0045] When the target hydraulic cylinder is detected to be deviating from the mechanical dead point and its effective lever arm reaches the preset starting lever arm threshold, the floating state of the target hydraulic cylinder is terminated.

[0046] The joint degrees of freedom corresponding to the target hydraulic cylinder are restored in the preset boom kinematic model, and control commands to maintain the target's stable hooking path are generated based on the restored full-degree-of-freedom kinematic model.

[0047] By adopting the above technical solution, the equivalent load torque acting on the target hydraulic cylinder is monitored in real time. When the torque drops to a preset recovery threshold, the cylinder is switched to a floating state that allows passive displacement. A dead-point disengagement command is then issued to the remaining unlocked joints. The linkage effect generated by the active displacement of the remaining joints drags the target hydraulic cylinder away from the mechanical dead point. Once its effective lever arm reaches the starting threshold, the floating ends and full-degree-of-freedom control is restored. This mechanism avoids the target hydraulic cylinder from starting under load at the mechanical dead point. It utilizes the mechanical linkage characteristics of the multi-section folding arm to achieve passive disengagement of the target joint, reducing the risk of instantaneous high-pressure impact and mechanical jamming caused by forcibly establishing hydraulic driving force at dead points or limit points. It improves the reliability of the boom system's smooth transition from a rigid passive support state to a full-degree-of-freedom active control state and extends the service life of the hydraulic actuators.

[0048] In conjunction with some implementations of the first aspect, in some implementations, based on a preset boom kinematic model, a dead-point disengagement command is issued to the remaining unlocked joints, specifically including:

[0049] Obtain the Jacobian matrix of the preset boom kinematic model in the current spatial pose, and associate the remaining unlocked joints with the hook points of the garbage bin;

[0050] The optimization objective is to maximize the axial displacement of the piston rod of the target hydraulic cylinder, and the constraint is that the change in the spatial coordinates of the garbage bin hook point is less than the preset anti-shaking threshold. The zero-space motion solution of the Jacobian matrix is ​​then solved.

[0051] The zero-space motion solution is transformed into the driving position increment of the remaining unlocked joints, generating a dead-point disengagement command.

[0052] By employing the aforementioned technical solution, the Jacobian matrix relating the remaining unlocked joints to the hook points of the garbage container is obtained. The optimization objective is to maximize the axial displacement of the target hydraulic cylinder piston rod, with the constraint that the change in the spatial coordinates of the hook points is less than a preset anti-shake threshold. The zero-space motion solution of this Jacobian matrix is ​​then solved and transformed into a drive position increment to generate a dead-point release command. This optimization process fully utilizes the zero-space motion characteristics of the redundant robotic arm. Under the condition of strictly limiting the spatial position fluctuation of the end hook point, the motion capability of the remaining joints is centrally allocated to maximize the dragging displacement of the target hydraulic cylinder. This solution enables the target hydraulic cylinder to escape the mechanical dead-point region along the optimal path and at the fastest speed, effectively reducing the disorderly shaking of the garbage container caused by multi-joint linkage during dead-point release, and improving the end-point trajectory control accuracy and escape efficiency of the boom during the complex posture recovery phase.

[0053] In a second aspect, embodiments of this application provide a hooking path planning system for a folding boom hook-lift garbage truck. The hooking path planning system for the folding boom hook-lift garbage truck includes: one or more processors and a memory; the memory is coupled to one or more processors, and the memory is used to store computer program code, the computer program code including computer instructions, and the one or more processors call the computer instructions to cause the system to perform the method described in the first aspect and any possible implementation thereof.

[0054] Thirdly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a system, cause the system to perform the method described in the first aspect and any possible implementation thereof.

[0055] Fourthly, embodiments of this application provide a computer program product that, when run on a system, causes the system to execute the method described in any possible implementation of the first aspect.

[0056] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0057] 1. This application provides a hooking path planning method for a folding boom type garbage truck. By acquiring data on the garbage container's center of gravity offset and vehicle attitude tilt angle, an initial joint motion trajectory is generated. Combined with a dynamic model, the load torque sequence is calculated, enabling precise location of abrupt trajectory segments where the torque change rate exceeds a threshold, as well as the target folding boom. Based on this, the compensation torque required to eliminate torque abrupt changes is calculated. The redundant degrees of freedom of multiple folding boom sections are used to obtain the joint compensation amount of other cooperating folding boom sections, and this compensation amount is integrated into the initial trajectory. This process, while strictly maintaining the hooking spatial trajectory at the end of the boom, shares the transient overload torque of the target folding boom through the cooperative movement of other folding boom sections, reducing the mechanical impact on the hydraulic system caused by local torque abrupt changes due to garbage container eccentricity or vehicle tilt. This solution smooths the force fluctuations of each joint, improving the stability and safety of the boom during hooking operations under complex working conditions. This suppresses mechanical vibrations generated by the boom under complex stress states, improving the position control accuracy and lifting stability of the hooking and docking of heavy-duty garbage containers.

[0058] 2. This application provides a hooking path planning method for a folding boom arm of a garbage truck. By monitoring the working pressure of the hydraulic cylinder in real time, when it is identified that the target hydraulic cylinder pressure is continuously exceeding the limit due to a large static off-center load, the folding arm is controlled to perform redundant posture adjustments while maintaining the end hooking point unchanged. This causes the target joint to move to the mechanical dead point or structural limit point and lock its hydraulic circuit. This mechanism switches the force mode of the target joint from hydraulic active drive to mechanical rigid support, using the physical limit of the metal structure to directly bear the extreme destructive force generated by the large off-center load. Subsequently, the joint is removed from the kinematic model, and the control command is regenerated using the remaining unlocked joints, so that the system can still maintain the predetermined hooking path even under extreme working conditions where some joints are passively locked. This scheme effectively reduces the risk of the target hydraulic cylinder being in a high-pressure overflow state for a long time under severe off-center load, reduces the probability of damage to hydraulic components, and significantly improves the ultimate load-bearing capacity and operational fault tolerance of the boom arm system in the face of extreme working conditions.

[0059] 3. This application provides a hook path planning method for a folding boom arm of a garbage truck. By real-time monitoring of the equivalent load torque acting on the target hydraulic cylinder, when the torque drops to a preset recovery threshold, the cylinder is switched to a floating state that allows passive displacement. A dead-point disengagement command is issued to the remaining unlocked joints. The linkage effect generated by the active displacement of the remaining joints drags the target hydraulic cylinder away from the mechanical dead point. Once its effective lever arm reaches the starting threshold, the floating ends and full-degree-of-freedom control is restored. This mechanism avoids direct load-bearing start-up of the target hydraulic cylinder at the mechanical dead point. It utilizes the mechanical linkage characteristics of the multi-section folding boom to achieve passive disengagement of the target joint, reducing the risk of instantaneous high-pressure impact and mechanical jamming caused by forcibly establishing hydraulic driving force at dead points or limit points. It improves the reliability of the boom arm system's smooth transition from a rigid passive support state to a full-degree-of-freedom active control state and extends the service life of the hydraulic actuators. Attached Figure Description

[0060] Figure 1 This is a structural schematic diagram of a folding arm type hook frame for garbage trucks provided in an embodiment of this application.

[0061] Figure 2 This is a schematic diagram of the structure of a garbage truck folding arm boom in the state of loading a garbage container, according to an embodiment of this application.

[0062] Figure 3 This is a schematic diagram of the structure of a garbage truck folding arm boom in the unloading state of the garbage container, provided by an embodiment of this application.

[0063] Figure 4 This is a flowchart illustrating a hook path planning method for a folding arm hook-lift garbage truck according to an embodiment of this application.

[0064] Figure 5 This is another flowchart illustrating a hook path planning method for a folding arm hook-lift garbage truck according to an embodiment of this application.

[0065] Figure 6 This is another flowchart illustrating a hook path planning method for a folding arm hook-lift garbage truck according to an embodiment of this application.

[0066] Figure 7 This is a schematic diagram of the physical device structure of a hook path planning system for a folding arm type garbage truck provided in an embodiment of this application. Detailed Implementation

[0067] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to any or all possible combinations including one or more of the listed items.

[0068] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0069] First, this application describes a folding boom type hook-lift mechanism for garbage trucks. Please refer to [link / reference]. Figure 1 , Figure 1 This is a structural schematic diagram of a folding boom type hook-lift for garbage trucks, provided as an embodiment of this application. The folding boom type hook-lift includes a hook-lift assembly, which mainly consists of a folding right-angle boom, a folding main boom, a lifting boom, a folding cylinder, a lifting cylinder, a tilting bracket, and a sub-beam frame. These seven core components are manufactured using high-strength steel and are connected as a whole through cylinder fulcrums A, B, C, D, E, F, G, and H, ensuring extremely high stability and durability of the device during lifting and transportation.

[0070] Specifically, one end of the folding right-angle arm is connected to the hook head of the hook arm at fulcrum A by a fixing pin, and the other end is fixedly welded to the folding main arm with a high-strength reinforced bushing plate on the outermost layer, welded to point B on both the inside and outside. Similarly, the piston rod end of the folding cylinder is connected to one end of the folding main arm at point C by a fixing pin, and the other end of the folding cylinder is connected to the lifting arm at point D by a fixing pin. Point D forms the rotation axis of the folding main arm. The lifting arm and the piston rod end of the lifting cylinder are hinged at hinge fulcrum F, and the cylinder head end of the lifting cylinder is hinged to the front end of the sub-beam frame at fixed fulcrum E. Point E serves as the rotation axis of the arm assembly. The rear end of the tilting bracket is hinged to the hinge fulcrum at the rear of the sub-beam frame (the center points are on the same axis).

[0071] Regarding the safety locking mechanism, a truck bed locking hook and locking cylinder are installed on the subframe. This locking cylinder features a safety interlock logic; that is, when the locking cylinder is not engaged, other button operations will have no effect, preventing worker misoperation from both physical and logical perspectives, greatly improving operational safety. Furthermore, a locking cylinder is built into the lifting arm. By controlling the extension and retraction of the locking cylinder's locking head, the operating mode can be switched: when the locking cylinder actuates and the locking head is in position, the boom can load and unload garbage containers or multi-functional garbage containers centered at point G; when the locking cylinder retracts inside the lifting arm, the boom can self-unload and dump garbage from the garbage container centered at point H.

[0072] Regarding the hydraulic drive system, this application represents a significant and targeted improvement. Addressing the safety hazards of traditional boom cranes where only a few cylinders engage during heavy-duty loading, resulting in insufficient pulling force that prevents loading of containers or even causes engine stalling and vehicle instability, this application employs a novel hydraulic system. This system is equipped with a batch of specially developed new hydraulic cylinders with self-relief capabilities. These cylinders maintain high-power pulling force even at low engine speeds, effectively reducing fuel consumption and fundamentally solving the problem of insufficient power for loading heavy-duty garbage. Simultaneously, the self-relief function effectively alleviates internal pressure buildup in the hydraulic system, extending the service life of the hydraulic cylinders and pipelines, avoiding frequent maintenance, and reducing overall lifecycle costs.

[0073] Furthermore, this new hydraulic system works in conjunction with a dedicated electromagnetic buffer valve assembly and a high-precision electromagnetic sensor. Through the coordinated control of multiple hydraulic cylinders, the hydraulic system operates more directly, and the control valves are extremely sensitive. The driver can easily operate the system from the driver's seat without leaving the cab, achieving precise alignment and locking of the boom hook and the center point of the box.

[0074] When loading garbage containers, the folding boom lift uses a folding hook mechanism to smoothly lift and place the container in the designated position on the vehicle. Throughout the process, electromagnetic buffer valves and sensors ensure smooth and safe operation, preventing unnecessary damage to the garbage container and the vehicle itself. After loading, the vehicle will carry the garbage container back to the processing center or transfer station for subsequent garbage processing or transfer. The specific working configuration is as follows: Figure 2 As shown, Figure 2 This application provides a schematic diagram of the structure of a garbage truck folding arm boom in the state of loading a garbage container.

[0075] During the unloading process of the folding boom lift, the folding hook mechanism will once again play a role, safely and smoothly unloading the garbage container to the designated position through reverse operation, so that subsequent emptying or replacement operations can be carried out. The specific working configuration is as follows: Figure 3 As shown, Figure 3 This application provides a schematic diagram of the structure of a garbage truck folding arm boom in the state of unloading the garbage container.

[0076] The following example is used in conjunction with Figure 4 The following describes a hook path planning method for a folding boom type garbage truck according to an embodiment of this application:

[0077] Please see Figure 4 This is a flowchart illustrating a hook path planning method for a folding arm hook-lift garbage truck according to an embodiment of this application.

[0078] S401. Obtain the center of gravity offset data of the target garbage container and the current vehicle attitude tilt angle data, and combine them with the preset boom kinematic model to generate the initial joint motion trajectory that satisfies the end hook position constraint.

[0079] The system acquires data including the target garbage container (e.g., standard compressed garbage container, open construction waste container), center of gravity offset data (e.g., lateral offset distance, longitudinal offset distance), current vehicle (e.g., heavy-duty sanitation chassis vehicle, light-duty hooklift truck), attitude tilt angle data (e.g., chassis roll angle, pitch angle), preset hooklift kinematic model (e.g., spatial linkage kinematic model, DH parameter model), end hook position constraints (e.g., hook point spatial coordinates, attitude angle limits), and initial joint motion trajectory (e.g., angular displacement sequence, angular velocity curve). In actual garbage collection operations, vehicles often face uneven ground and uneven garbage distribution inside the container, leading to off-center loading. Generating this trajectory is to establish a basic motion planning benchmark based on actual physical deviations. This improves the spatial positioning accuracy of the hooklift during the initial approach phase and reduces the probability of inaccurate hook point alignment due to terrain or off-center loading.

[0080] Tilt sensors and laser rangefinders mounted on the vehicle chassis and boom can be used to collect attitude tilt angle data and center of gravity offset data in real time. This data is then input into a pre-defined boom kinematic model constructed based on the standard parametric method. By setting the end-hook position constraint as the target pose, inverse kinematics is solved using geometric algebra to calculate the desired angles of each joint at each time point. These discrete angle data are then smoothed using a cubic spline interpolation algorithm to generate continuous initial joint motion trajectories that satisfy spatial constraints.

[0081] Alternatively, this process can be implemented by constructing and training a deep feedforward neural network model. This model can learn the nonlinear mapping relationship between complex spatial constraints and joint angles through a large amount of historical data. The acquired center of gravity offset data and attitude tilt angle data are used as input features of the neural network. The hidden layers of the network process these features through activation functions, directly outputting a sequence of joint angles that satisfy the end-hook position constraints. The output sequence is then validated using a forward kinematics algorithm to remove singularities exceeding mechanical limits, ultimately generating the initial joint motion trajectory.

[0082] S402. Based on the initial hook trajectory and the preset boom dynamic model, calculate the load torque sequence of each folding boom under the initial hook trajectory;

[0083] The initial hook trajectory is the angular displacement sequence generated in the previous step. A preset boom dynamics model (e.g., Newton-Euler dynamics model, Lagrange dynamics model) is used to describe the relationship between force and motion, and the load torque sequence (e.g., discrete torque time sequence, continuous torque change curve) reflects the stress situation. Relying solely on the kinematic trajectory can only define changes in spatial position and cannot predict the physical stresses experienced by the mechanical structure during motion. Calculating the load torque sequence is to anticipate the internal loads on the robotic arm under planned motion. This improves the predictability of the system's physical response and reduces the risk of unforeseen mechanical overloads during actual operation.

[0084] A pre-defined boom dynamics model based on the Newton-Euler iterative method can be used for calculation. First, the first and second order numerical derivatives of the initial hook trajectory are performed to obtain the angular velocity and angular acceleration of each folding arm at various time points. Then, a forward recursion is performed from the base of the boom towards the end to calculate the velocity and acceleration of the center of mass of each link, thereby obtaining the inertial force and inertial torque of each folding arm. Next, a backward recursion is performed from the end towards the base, combining the mass and moment of inertia of each folding arm to calculate the required driving torque for each joint, and the torque values ​​at each time point are arranged in chronological order to form a load torque sequence.

[0085] This can also be achieved using multibody dynamics simulation technology. A virtual simulation environment containing the precise geometry, mass distribution, and material properties of the boom is built into the computing system as a preset boom dynamic model. The initial hook trajectory is input as the drive signal to the virtual joint actuators within this virtual simulation environment. The dynamics simulation engine is run, performing forward dynamic calculations at a set time step. During the simulation, virtual torque sensors extract the force data at each folding arm joint in real time. This data is exported and stitched together along the time axis to obtain the load torque sequence.

[0086] S403. Traverse the load torque sequence, identify the trajectory segments where the torque change rate is greater than the preset torque change rate threshold as abrupt trajectory segments, and extract the target folding arm that generates torque abrupt changes within the abrupt trajectory segments.

[0087] The core concepts of this step are: preset torque change rate thresholds (e.g., maximum permissible torque derivative, safety gradient limits, derived from the maximum safe pressure gradient of the hydraulic system or the fatigue limit of the mechanical structure, serving as the safe upper limit boundary of the actually calculated torque change rate), abrupt trajectory segments (e.g., specific time windows, specific angle intervals), and target folding arms (e.g., main lifting arm, auxiliary telescopic arm). In complex torque sequences, not all stages present danger. Traversal and extraction are performed to precisely isolate specific moments and specific mechanical components that will experience drastic stress changes. This concentrates optimization computation on the most critical nodes, reduces unnecessary computation on safe trajectory segments, and improves the overall computational efficiency of path planning.

[0088] The central difference algorithm can be used to numerically differentiate the load torque sequence to obtain the torque change rate at each discrete time point. A fixed-length sliding time window is set and gradually moved along the time axis. At each slide, the torque change rate within the window is compared with a preset torque change rate threshold. When it is found that the torque change rate of multiple consecutive sampling points is greater than the preset torque change rate threshold, the start and end times of these sampling points are recorded, and this time interval is defined as the abrupt change trajectory segment. At the same time, the joint numbers that generated the above abnormal data within this time interval are read, and the corresponding robotic arms are marked as the target folding arm.

[0089] Wavelet transform algorithms can also be introduced for time-frequency domain analysis of the load torque sequence. Using the load torque sequence as the input signal, a suitable wavelet basis function is selected for multi-scale decomposition. Drastic changes in torque will manifest as modulus maxima in the high-frequency band after wavelet transform. A preset torque change rate threshold is converted into a corresponding high-frequency energy threshold. The high-frequency coefficients after decomposition are scanned; when the energy of a certain coefficient exceeds the high-frequency energy threshold, an inverse transform is used to locate the specific time period in the original sequence, identifying it as the abrupt change trajectory segment. The data channel identifier to which this signal segment belongs is extracted, thereby determining the target folding arm that caused the torque abrupt change.

[0090] S404. Calculate the target compensation torque required for the target folding arm to eliminate torque abrupt changes within the abrupt trajectory segment;

[0091] The target compensation torque (e.g., reverse torque vector, corrective torque amplitude) represents the amount of overload that needs to be offset. Simply identifying the sudden change in force is insufficient; the system must quantify how much mechanical unloading is required to restore the component to a safe state. Calculating this value provides a precise mathematical target for subsequent torque redistribution. This reduces the probability of hydraulic failure or structural damage to the target component and improves the quantitative control accuracy of the entire mechanical system under extreme conditions.

[0092] A low-pass filtering algorithm can be used to obtain the ideal smooth torque. The raw torque data of the target folding arm within the abrupt change trajectory segment is extracted and input into a Butterworth low-pass filter to remove high-frequency components representing torque abrupt changes, resulting in a smooth ideal torque curve. At each time point within the abrupt change trajectory segment, the raw torque data is subtracted from the corresponding value on the ideal torque curve. The calculated difference sequence is used as the target compensation torque required to eliminate torque abrupt changes; this sequence accurately reflects the overload that needs to be offset at each moment.

[0093] Alternatively, calculations can be performed using adaptive envelope fitting technology. Polynomial curve fitting is applied to the stable torque data of the target folding arm before and after the abrupt change in trajectory segment, extrapolating the trend into the abrupt change trajectory segment to construct a baseline torque envelope representing the normal stress state. Within the abrupt change trajectory segment, the vertical distance between the actual load torque sequence and this baseline torque envelope is calculated point-by-point. These distance values ​​are converted into torque values ​​and assigned a sign opposite to the original abrupt change direction, thus obtaining the target compensation torque required for the target folding arm to eliminate torque abrupt changes within the abrupt change trajectory segment.

[0094] S405. Under the constraint of keeping the spatial trajectory of the hook at the end of the boom unchanged, based on the target compensation torque and the preset boom dynamic model, use the redundant degrees of freedom of the multi-section folding arm to calculate the joint compensation amount of other folding arms that move in coordination with the target folding arm.

[0095] Under the constraint of keeping the spatial trajectory of the hook at the end of the boom unchanged, based on the target compensation torque and the preset boom dynamics model, and utilizing the redundant degrees of freedom of the multi-section folding arm, the joint compensation amounts of other folding arms that move in coordination with the target folding arm are calculated, specifically including:

[0096] Based on a pre-set boom dynamics model, the redundant motion space that other folding arms can execute is extracted without changing the spatial trajectory of the boom end hook. The dynamic load margin of other folding arms in the current motion posture is obtained. The dynamic load margin is used to characterize the safety threshold that each other folding arm can withstand additional torque without overload. According to the dynamic load margin, the target compensation torque is weighted and distributed in the redundant motion space to obtain the equivalent compensation torque shared by each other folding arm. According to the equivalent compensation torque and the pre-set boom dynamics model, the joint compensation amount of other folding arms is calculated in reverse.

[0097] Redundant degrees of freedom (e.g., redundant rotary joints, additional telescopic joints), joint compensation amounts (e.g., angle adjustment values, linear displacement adjustment amounts), redundant motion space (e.g., the null space of the Jacobian matrix, self-moving manifold), dynamic load margin (e.g., available torque capacity, safety stress margin, derived from the difference between the rated maximum torque of the folding arm and the current actual torque, serving as the safe upper limit threshold for equivalent compensation torque allocation), and equivalent compensation torque (e.g., allocated torque share, shared torque vector) constitute the basis of cooperative motion. To alleviate local overload without altering the end-effector trajectory, the redundancy characteristics of the mechanical structure must be fully utilized to transfer stress. This reduces the peak stress of individual components and improves the overall structural stress balance and load distribution efficiency.

[0098] The Jacobian matrix of the boom system can be calculated, and its null space can be obtained through singular value decomposition, thereby extracting the redundant motion space without changing the end effector pose. The rated maximum torque of each other folding arm is read in real time, and its actual load torque in the current posture is subtracted to obtain the dynamic load margin. A diagonal weight matrix is ​​constructed using the dynamic load margin as a weighting factor. A weighted pseudo-inverse algorithm is used to map and distribute the target compensation torque to other folding arms within the redundant motion space, obtaining the equivalent compensation torque. Finally, the equivalent compensation torque is multiplied by the compliance coefficient matrix of each joint, and the joint compensation of other folding arms is calculated inversely based on the preset boom dynamics model.

[0099] This process can also be transformed into a constrained nonlinear optimization problem. The objective function is set as minimizing the difference between the sum of the torques shared by the other folding arms and the target compensation torque. The extracted redundant motion space is used as an equality constraint to ensure that the end-effector trajectory remains unchanged; the obtained dynamic load margin is used as an inequality constraint to ensure that the allocated torque does not exceed the safety threshold. A sequential quadratic programming algorithm is used to iteratively solve this optimization problem, finding the optimal torque allocation scheme under the premise of satisfying all constraints, and obtaining the equivalent compensation torque. Then, based on the partial derivative relationship between torque and angle in the preset boom dynamic model, the corresponding joint compensation amount is derived in reverse.

[0100] S406. Integrate the joint compensation amount into the initial joint motion trajectory of each folding arm in the abrupt trajectory segment to reconstruct the target smooth hooking path.

[0101] The joint compensation amount is integrated into the initial joint motion trajectory of each folding arm within the abrupt trajectory segment to reconstruct the target smooth hooking path, specifically including:

[0102] The entry and exit nodes of the abrupt trajectory segment in the initial joint motion trajectory are determined, and the initial motion state data of the initial joint motion trajectory at the entry and exit nodes are extracted. Based on the initial motion state data, a smooth transition function matching the two ends of the abrupt trajectory segment is constructed. The joint compensation amount is modulated in the time domain using the smooth transition function to obtain the modulated target joint compensation amount, so that the value and rate of change of the target joint compensation amount at the entry and exit nodes are both close to zero. The target joint compensation amount is superimposed on the initial joint motion trajectory of each folding arm in the abrupt trajectory segment to reconstruct the target smooth hooking path.

[0103] The key elements for path reconstruction are: the target smooth hooking path (e.g., the final optimized trajectory array, smoothed motion sequence), the entry node (e.g., the mutation start timestamp, starting angle index), the exit node (e.g., the mutation end timestamp, ending angle index), the initial motion state data (e.g., angular position, angular velocity, angular acceleration at the node), the smooth transition function (e.g., cubic spline function, fifth-order polynomial function), the temporal modulation (e.g., multiplication by a window function, amplitude scaling on the time axis), and the target joint compensation (e.g., the modulated adjustment value, the scaled compensation sequence). Directly superimposing the compensation values ​​will result in new motion steps at the start and end of the compensation. Temporal modulation and fusion are performed to seamlessly embed the calculated adjustment values ​​into the original plan. This improves the kinematic continuity of the robotic arm and reduces the secondary mechanical shocks generated during the transition phase.

[0104] By traversing the timeline of the initial joint motion trajectory, the start and end timestamps of abrupt trajectory segments can be precisely located and used as entry and exit nodes, respectively. Position and velocity are extracted at these nodes as initial motion state data. A fifth-degree polynomial is constructed as a smooth transition function, and boundary conditions are set using the initial motion state data to ensure that the function's values ​​at both endpoints, its first derivative, and its second derivative are all zero. The calculated joint compensation is multiplied point-by-point in the time domain with this smooth transition function to achieve temporal modulation and obtain the target joint compensation. Finally, the target joint compensation is aligned in time and directly added to the initial joint motion trajectory to reconstruct a smooth hooking path for the target.

[0105] Run-length encoding can be used to determine the index range of the abrupt trajectory segment, extracting the indices at both ends as the entry and exit nodes, and reading the corresponding kinematic parameters as initial motion state data. A Bézier curve is used to construct a smooth transition function, and control points for the Bézier curve are set based on the initial motion state data to ensure that the tangent slope of the curve is zero at entry and exit. The time variable is mapped to the parameter space of the Bézier curve, and the modulation coefficient at each moment is calculated. This coefficient is used to perform temporal modulation scaling on the joint compensation amount to obtain the target joint compensation amount. This compensation amount is then superimposed onto the initial joint motion trajectory matrix within the abrupt trajectory segment in the form of matrix addition, thereby reconstructing the target smooth hooking path.

[0106] S407. Output control commands to each hydraulic cylinder according to the target smooth hooking path.

[0107] Hydraulic cylinders (such as main lifting cylinders and telescopic boom cylinders) and control commands (such as proportional valve opening signals and pulse width modulation voltage signals) are the objects at the execution level. After all the calculations and optimizations in the preceding steps, the final result is a digital ideal path, which needs to be translated into actual actions in the physical world. Outputting commands according to the target path is to perfectly map the digital plan to mechanical execution. This improves the motion accuracy of the physical hooking process and reduces the possibility of operational deviations during the actual execution phase.

[0108] By utilizing the geometric mapping relationship of the boom, the sequence of joint angles along the target's smooth hooking path can be converted into the expected extension / retraction length sequence of the corresponding hydraulic cylinders. Referring to a pre-calibrated hydraulic system control mapping table, the expected extension / retraction length is converted into the corresponding proportional directional valve control voltage value. These voltage values ​​are then packaged into standard controller area network (CLAN) messages and sent as control commands to the underlying hydraulic controller, which then drives the corresponding hydraulic cylinders to move along the planned path.

[0109] Alternatively, a closed-loop proportional-integral-derivative (PID) control architecture can be constructed to achieve command output. The target smooth hooking path is used as the system's reference input signal, while a linear displacement sensor mounted on the hydraulic cylinder collects the current actual position signal in real time. The difference between the reference signal and the actual signal is compared to obtain the position deviation. This deviation is input to the PID controller for calculation, and the output pulse-width modulation (PWM) signal with adjustable duty cycle serves as the control command. This command directly acts on the hydraulic pump and servo valve, precisely controlling the flow and pressure of the hydraulic cylinder, thereby driving it to move along the target path.

[0110] In the above embodiments, by acquiring data on the weight center offset of the garbage container and the vehicle's attitude tilt angle, an initial joint motion trajectory is generated. Combined with a dynamic model, the load torque sequence is calculated, enabling precise location of abrupt trajectory segments where the torque change rate exceeds a threshold, as well as the target folding arm. Based on this, the compensation torque required to eliminate torque abrupt changes is calculated. The redundant degrees of freedom of the multi-section folding arm are used to determine the joint compensation amount of other cooperating folding arms, which is then integrated into the initial trajectory. This process, while strictly maintaining the hook-and-hook spatial trajectory at the end of the boom, shares the transient overload torque of the target folding arm through the cooperative movement of other folding arms, reducing the mechanical impact on the hydraulic system caused by local torque abrupt changes due to garbage container off-center loading or vehicle tilting. This solution smooths the force fluctuations of each joint, improving the stability and safety of the boom during hook-and-hook operations under complex conditions. This suppresses mechanical vibrations generated by the boom under complex stress states, improving the position control accuracy and lifting stability of the heavy-duty garbage container hook-and-hook docking.

[0111] In the above embodiments, dynamic compensation of redundant degrees of freedom effectively solves the problem of sudden torque changes under conventional operations, ensuring the stability of the hooking path. However, in actual complex operating scenarios, if there is an extreme static large off-center load inside the garbage container, dynamic compensation of multiple joints alone may not completely eliminate the risk of continuous overpressure in local hydraulic cylinders, and long-term operation may still lead to overload damage to hydraulic components. To cope with such extreme off-center load conditions and further improve the ultimate load-bearing capacity and operational fault tolerance of the boom system, this application provides another hooking path planning method for a folding boom type garbage truck, based on the above embodiments. The following is combined with... Figure 5 The following describes another method for planning the hooking path of a folding boom type garbage truck in the embodiments of this application:

[0112] Please see Figure 5 This is another flowchart illustrating a hook path planning method for a folding arm hook-lift garbage truck according to an embodiment of this application.

[0113] S501. Obtain the real-time working pressure of each hydraulic cylinder when performing joint compensation.

[0114] Real-time operating pressures, such as rodless chamber pressure and rod chamber pressure, are collected to continuously monitor the actual stress state of the underlying physical actuators during system compensation actions. Theoretically calculated torques alone cannot fully reflect the additional resistance caused by friction, hydraulic oil temperature variations, or extreme off-center loads in the real physical world. This improves the system's awareness of the underlying hardware's operating status and reduces the probability of hydraulic components being unknowingly damaged due to discrepancies between theoretical models and actual physical conditions.

[0115] Data can be acquired by directly installing high-frequency dynamic pressure sensors at the inlet and outlet of each hydraulic cylinder. During hydraulic system operation, the pressure sensors continuously monitor the fluid pressure within the oil circuit and convert it into standard analog voltage or current signals. These analog signals are then sampled at high speed using a high-precision analog-to-digital converter, digitizing them. The digitized pressure data is transmitted to the central controller via the controller's local area network bus. The central controller performs Kalman filtering on the received data to eliminate transient high-frequency noise caused by hydraulic pump pulsation, thus obtaining a smooth and accurate real-time operating pressure for each hydraulic cylinder.

[0116] Indirect observation and calculation can also be performed based on the overall output status of the hydraulic pump station and the parameters of each control valve. A total pressure sensor is installed on the main output pipeline of the hydraulic pump to obtain the main system pressure, while the valve core displacement data and flow rate data of the proportional directional valves corresponding to each hydraulic cylinder are read in real time. Using the pre-established hydraulic valve orifice throttling characteristic equation and Bernoulli's principle in fluid mechanics, the pressure drop of hydraulic oil flowing through each proportional directional valve is calculated. The pressure drop of the corresponding pipeline and valve orifice is subtracted from the main system pressure, and the back pressure generated by the hydraulic cylinder due to its own weight and friction is compensated, thereby deriving the real-time working pressure inside each hydraulic cylinder.

[0117] S502. When the real-time working pressure of the target hydraulic cylinder is continuously greater than the preset pressure threshold, it is determined that the garbage container has a large static off-center load.

[0118] Target hydraulic cylinders include, for example, main lifting cylinders with abnormal pressure or overloaded auxiliary telescopic cylinders. Preset pressure thresholds, such as the critical value for safe overflow pressure or the upper limit of rated working pressure, are derived from the maximum safe rating parameters of the hydraulic components at the time of manufacture. These thresholds serve as the baseline limits for determining whether the system is in a dangerous overload state. Static large off-center loads include, for example, excessive weight loading at the front of the tank or severe accumulation of waste on one side leading to extreme shifts in the center of gravity. This determination is made to distinguish between instantaneous dynamic impacts and sustained physical overloads. Dynamic impacts can be mitigated by brief torque distribution, while sustained overpressure signifies a breach of physical limits. This improves the system's accuracy in identifying extreme operating conditions and reduces the risk of taking ineffective compensation measures due to misjudging them as ordinary dynamic fluctuations.

[0119] A sliding time window integration algorithm can be used for this determination. A fixed-length observation window is set in the control system, and this window slides continuously across the real-time acquired working pressure data stream over time. Within each sampling period, the real-time working pressure of the target hydraulic cylinder is compared with a preset pressure threshold, and the pressure difference exceeding the threshold is calculated. Time integration is performed on all positive pressure differences within the window to obtain an integral value representing the accumulated overpressure energy. When this integral value exceeds a preset energy tolerance limit, it indicates that the overpressure phenomenon is not only large in magnitude but also long in duration. At this point, the system formally determines that the garbage container has a large static off-center load.

[0120] A finite state machine logic combined with a continuous counting mechanism can also be introduced to implement the judgment. A state machine model is constructed, including normal, warning, and off-center load states. The system defaults to the normal state. When the real-time working pressure of the target hydraulic cylinder is detected to be greater than a preset pressure threshold, the state machine jumps to the warning state and starts a high-frequency timer or counter. In the warning state, if the pressure data remains above the preset pressure threshold for several consecutive sampling periods, and the counter reaches a preset overflow value, the state machine jumps to the off-center load state and outputs the judgment result. If the pressure falls below the threshold during this period, the counter is reset to zero, and the state machine returns to the normal state.

[0121] S503. Under the constraint of keeping the current spatial position of the end hook point of the boom unchanged, control the multi-section folding boom to perform redundant posture adjustment until the joint corresponding to the target hydraulic cylinder moves to the preset mechanical dead point position or the preset structural limit point.

[0122] Under the constraint of keeping the current spatial position of the end hook point of the boom unchanged, control the multi-section folding boom to perform redundant attitude adjustments until the joint corresponding to the target hydraulic cylinder moves to the preset mechanical dead point position or the preset structural limit point, specifically including:

[0123] The target hydraulic cylinder is set as the master retraction actuator, and the other hydraulic cylinders in the multi-section folding arm, excluding the target hydraulic cylinder, are set as driven compensation actuators. A fine-tuning displacement command is generated according to a preset safety step size, causing the master retraction actuator to move unidirectionally towards a preset mechanical dead point or a preset structural limit point. Based on a preset boom kinematic model, a virtual offset vector is calculated, indicating the deviation of the end hook point from its current spatial position when the master retraction actuator executes the fine-tuning displacement command alone. With the goal of counteracting the virtual offset vector, synchronous compensation displacement commands corresponding to each driven compensation actuator are generated through inverse kinematics calculation. The fine-tuning displacement command and the synchronous compensation displacement command are issued and executed synchronously as a linkage control cycle, and the process returns to the step of setting the target hydraulic cylinder as the master retraction actuator, until the master retraction actuator reaches the preset mechanical dead point or the preset structural limit point.

[0124] End-point hooking points include, for example, the tip of the boom hook and the center of the docking beam. Main retraction actuators include, for example, actively retracting force-bearing cylinders and actively extending load-bearing cylinders. Driven compensation actuators include, for example, adjusting auxiliary boom cylinders and coordinating main boom cylinders. Preset safety step lengths include, for example, fixed millimeter-level displacement and minute angle increments. Fine-tuning displacement commands include, for example, single-step retraction signals and minute extension commands. Virtual offset vectors include, for example, three-dimensional spatial coordinate differences and attitude angle deviations. Synchronous compensation displacement commands include, for example, reverse motion signals and pose correction amounts. Linkage control cycles include, for example, millisecond-level control cycles and synchronous refresh time windows. Preset mechanical dead-point positions include, for example, the cylinder fully retracted to the bottom position and the cylinder fully extended to the top position. Preset structural limit points include, for example, mechanical stop contact points and limit pin clamping points. Redundant attitude adjustments are performed to actively change the stress pattern of the mechanical structure without disrupting the current working space constraints. Guiding the joint with the greatest stress to its physical limit position utilizes the physical rigidity of the metal structure to replace the support of the hydraulic fluid. This increases the structural load-bearing capacity of the entire boom system under extreme conditions and reduces the probability of the hydraulic system bursting or leaking due to prolonged exposure to excessive high pressure.

[0125] This linkage control process can be implemented based on a zero-space mapping algorithm using the Jacobian matrix. First, a fine-tuning displacement command for the master retraction actuator is generated according to a preset safety step size. The virtual end-effector offset vector caused by this fine-tuning action is calculated using the forward kinematic equations of a preset boom kinematic model. Next, the Jacobian matrix composed of all driven compensation actuators in the current posture is calculated, and its pseudo-inverse matrix is ​​obtained. The inverse virtual offset vector is multiplied by this pseudo-inverse matrix to solve for the synchronous compensation displacement command of each driven compensation actuator in joint space. The fine-tuning displacement command and the synchronous compensation displacement command are packaged together in the same linkage control cycle and sent to the underlying servo driver. This process is iterated repeatedly, continuously monitoring the position feedback of the master retraction actuator until it triggers the limit switch installed at a preset mechanical dead point or preset structural limit point.

[0126] This process can also be accomplished using a numerical optimization iterative algorithm based on closed-loop feedback. At the beginning of each linkage control cycle, the master retractor actuator is advanced by a fine-tuning displacement command according to a preset safety step size. At this time, the end-point hook point will deviate. The difference between the unchanged target spatial position and the currently calculated offset position is used to obtain the virtual offset vector. A nonlinear optimization problem is constructed with the displacement of each driven compensation actuator as the independent variable and minimizing the virtual offset vector as the objective function. The objective function is solved quickly using the gradient descent method or Newton's iteration method to obtain the synchronous compensation displacement command that minimizes the end-point position error. The two sets of commands are sent and executed synchronously. The coordinates of the current position of the master retractor actuator are compared in real time with the preset mechanical dead point position or preset structural limit point position by an absolute encoder installed at the joint. Once the coordinates coincide or enter the minimum error band, the iteration stops.

[0127] S504. Lock the hydraulic circuit of the target hydraulic cylinder, so that the joint corresponding to the target hydraulic cylinder is switched from hydraulic drive to mechanical rigid support.

[0128] Hydraulic circuits include main inlet and return oil lines and control pilot lines. Mechanical rigid supports include direct force application to metal cylinders and physical load-bearing by mechanical stops. Locking the circuit and switching the support mode completely cuts off energy exchange between overloaded hydraulic components and the entire hydraulic power system. When a joint reaches its dead point or limit point, the fluid no longer has room for adjustment. At this time, valves are used to seal the oil, allowing the huge external off-center load to act directly on the heavy mechanical structural components, rather than on the fragile hydraulic seals. This improves the system's physical resistance to extreme static destructive forces and reduces the risk of severe thermal decay or mechanical fatigue damage to core components such as hydraulic pumps and proportional valves due to continuous high-pressure overflow.

[0129] Circuit locking can be achieved by controlling the solenoid directional valve and the two-way hydraulic control check valve in the hydraulic system. Upon receiving a signal that the target hydraulic cylinder has reached the designated position, the central controller immediately sends a power-off or reset signal to the solenoid directional valve controlling that cylinder, causing its valve core to return to the neutral position and cutting off the main oil supply circuit. Simultaneously, the two-way hydraulic control check valve, connected in series between the inlet and outlet of the hydraulic cylinder, closes rapidly under spring force after losing pilot control pressure. This completely seals off the hydraulic oil in both the rodless and rod chambers of the hydraulic cylinder, preventing flow and thus solidifying the hydraulic cylinder into a rigid connecting rod, achieving a physical switch from hydraulic drive to mechanical rigid support.

[0130] Alternatively, a specially designed electro-hydraulic interlocking mechanical pin mechanism can be used in conjunction with a logic valve assembly. A mechanical pin with an electromagnetic drive is installed at the joint corresponding to the target hydraulic cylinder. When the joint moves to the preset structural limit point, the controller first controls the unloading valve in the logic valve assembly to open, instantly releasing the high pressure in the target hydraulic cylinder circuit, placing it in a zero-pressure floating state. Subsequently, the controller sends an action command to the electromagnetic drive, driving the mechanical pin to precisely insert into the joint limit hole, completing a physical, absolute lock. After the pin is in place, the position sensor is triggered, and the controller accordingly completely closes all inlet and outlet logic valves of the cylinder, ensuring that the hydraulic system no longer outputs any power to it, relying entirely on the pin and limit block for mechanical rigidity support.

[0131] S505. Delete the joint degrees of freedom corresponding to the target hydraulic cylinder in the preset boom kinematic model, and regenerate the control commands to maintain the target's stable hooking path using the remaining unlocked joints.

[0132] Joint degrees of freedom include rotational and translational motion dimensions. Unlocked joints include normally functioning lifting joints and unrestricted telescopic joints. Deleting degrees of freedom and regenerating commands in the model allows the control algorithm to adapt to fundamental changes in the physical structure. When a joint is rigidly locked, the original multi-DOF kinematic model becomes invalid; without updates, the system will output incorrect control commands, leading to mechanical interference or tearing. Reconfiguring the model and planning the path allows the system to continue unfinished tasks using the remaining movable joints. This improves the operational continuity of the boom system under partially limited functionality and reduces the probability of the entire waste collection operation being interrupted due to a single joint locking.

[0133] Matrix dimensionality reduction and reconstruction techniques can be used to update the kinematic model and generate commands. In the control system's memory, the Jacobian matrix and transformation matrix corresponding to the original preset boom kinematic model are extracted. The matrix column or parameter dimension corresponding to the target hydraulic cylinder is located, and its column vector is directly removed from the Jacobian matrix. Simultaneously, the variables of that joint are replaced with fixed constants for locking in the homogeneous transformation matrix. After dimensionality reduction, a completely new low-order kinematic model is obtained. Using the original target smooth hooking path as input, this dimensionality-reduced low-order kinematic model is used to perform inverse kinematics solving again, calculating the new angles or displacements of the remaining unlocked joints at each time point, thereby generating a new sequence of control commands.

[0134] Graph theory and dynamic topology update algorithms can also be used to handle this. The boom system is abstracted as a directed acyclic graph model consisting of nodes and edges. When the target hydraulic cylinder is locked, the node attribute corresponding to the cylinder is changed from an active node to a passive rigid node in the graph theory model, and its two adjacent edges are merged into a rigid equivalent edge with a fixed angle or length. After updating the graph's topology, the directed acyclic graph is traversed again, automatically generating a new link parameter table and forward and inverse kinematic equations. Based on the updated equations, a polynomial interpolation algorithm is used, with the trajectory of the end hook point as a constraint, to recalculate the motion trajectory of the remaining unlocked joints and convert it into control commands executable by the underlying actuator.

[0135] In the above embodiments, by monitoring the working pressure of the hydraulic cylinder in real time, when it is identified that the target hydraulic cylinder pressure is continuously exceeding the limit due to a large static off-center load, the folding arm is controlled to perform redundant posture adjustments while maintaining the constraint that the end hook point remains unchanged. This causes the target joint to move to the mechanical dead point or structural limit point and lock its hydraulic circuit. This mechanism switches the force mode of the target joint from hydraulic active drive to mechanical rigid support, using the physical limit of the metal structure to directly bear the extreme destructive force generated by the large off-center load. Subsequently, the joint is removed from the kinematic model and the control command is regenerated using the remaining unlocked joints, so that the system can still maintain the predetermined hooking path even under extreme working conditions where some joints are passively locked. This scheme effectively reduces the risk of the target hydraulic cylinder being in a high-pressure overflow state for a long time under severe off-center load, reduces the probability of damage to hydraulic components, and improves the ultimate load-bearing capacity and operational fault tolerance of the boom system in the face of extreme working conditions.

[0136] Through the mechanical dead-point locking mechanism of the above embodiments, the boom system successfully resists the extreme destructive force caused by static large eccentric loads using mechanical rigid support, ensuring the safety of the equipment under harsh working conditions. However, when the boom changes its subsequent working posture, causing the eccentric load torque acting on the target hydraulic cylinder to gradually decrease and return to a safe range, the system needs to safely return from a passive mechanical rigid support state to a fully free active hydraulic control state. To avoid the risk of instantaneous high-pressure impact and mechanical jamming caused by directly forcibly starting under load at mechanical dead points or limit points, this application further provides another hooking path planning method for garbage truck folding boom booms. The following is combined with... Figure 6 This application describes another method for planning the hooking path of a folding boom crane for garbage trucks:

[0137] Please see Figure 6 This is another flowchart illustrating a hook path planning method for a folding arm hook-lift garbage truck according to an embodiment of this application.

[0138] S601. Real-time monitoring of the equivalent load torque of the boom arm acting on the target hydraulic cylinder in the current spatial position;

[0139] The current spatial pose includes the three-dimensional spatial coordinates of the boom and the current rotation angle of each joint. The equivalent load torque includes the equivalent thrust converted to the cylinder axis and the rotational torque mapped to the joint hinge points. Monitoring the equivalent load torque is crucial for real-time understanding of the force changes experienced by the locked joints during subsequent operations. As the overall posture of the boom changes, the force state of parts previously subjected to extreme off-center loads shifts. This improves the system's dynamic perception of the mechanical structure's stress state and reduces the risk of secondary overload caused by blindly unlocking before the stress has returned to a safe level.

[0140] Real-time data can be acquired using pin sensors and tilt sensors installed at each hinge point of the boom. The system reads the current spatial pose data through the tilt sensors and, combined with a preset boom dynamic model, calculates the gravity component and off-center load torque generated by the garbage container in the current posture. These torque data are calibrated and fused with the actual force data at the hinge points collected by the pin sensors. Using the mechanical equilibrium equation, the overall load torque is converted to the action axis of the target hydraulic cylinder, thereby calculating the equivalent load torque acting on the cylinder in real time.

[0141] A torque observer model based on a multilayer perceptron can also be constructed for monitoring. During model training, various attitude data of the boom, cylinder pressure data, and the corresponding actual equivalent load torque are used as samples for training, enabling the model to learn the nonlinear mapping relationship between attitude and torque. In actual operation, the real-time collected current spatial pose data is input into this torque observer model. The model's forward propagation algorithm directly outputs the predicted equivalent load torque value based on the currently input attitude characteristics, achieving real-time dynamic monitoring of the force state of the target hydraulic cylinder.

[0142] S602. When the equivalent load torque drops to the preset recovery threshold, the hydraulic circuit of the target hydraulic cylinder is switched to a floating state that allows passive displacement of the piston rod.

[0143] Preset recovery thresholds, such as the upper limit of safe working torque or a percentage of rated load torque, are derived from the conventional load-bearing capacity indicators of the hydraulic system. Their values ​​are necessarily lower than the torque equivalent corresponding to the preset pressure threshold mentioned earlier, serving as the lower limit boundary for judging whether the stress state has returned to safety. Passive piston rod displacement includes, for example, follow-up extension and retraction, and resistance-free sliding; floating states include, for example, the inlet and outlet oil circuits being connected, and the unloaded, pressure-free state. Switching to the floating state is to release the rigid physical lock on the target hydraulic cylinder after the stress has returned to safety, without immediately applying active hydraulic driving force. Directly applying pressure at the dead point can easily cause a huge hydraulic shock. This improves the compliance of the hydraulic system during state transitions and reduces the probability of mechanical jamming or seal damage caused by instantaneous high pressure build-up.

[0144] The floating state can be switched by controlling the solenoid directional valve assembly in the hydraulic system. When the central controller detects that the equivalent load torque continues to decrease and falls below the preset recovery threshold, it sends a specific control signal to the three-position four-way solenoid directional valve corresponding to the target hydraulic cylinder. This signal drives the valve spool of the directional valve to move to a special floating neutral position, making the rodless chamber, rod chamber, and return oil passage of the hydraulic cylinder interconnected. At this time, the hydraulic oil inside the hydraulic cylinder can flow freely back to the oil tank, and the piston rod can generate a passive displacement without resistance under the action of external mechanical force, thus successfully switching to the floating state.

[0145] State switching can also be achieved using a specially configured bypass unloading valve circuit. A bypass oil circuit with an electromagnetic proportional unloading valve is connected in parallel between the inlet and outlet ports of the target hydraulic cylinder. When the equivalent load torque meets the condition of decreasing to a preset recovery threshold, the controller outputs a gradually increasing pulse width modulation signal to the electromagnetic proportional unloading valve. The opening of the unloading valve gradually increases accordingly, smoothly releasing and connecting the pressure in the two chambers of the target hydraulic cylinder. This method not only realizes the floating of the hydraulic circuit, but also ensures the smooth transition of resistance when the piston rod is passively displaced through proportional control, further ensuring the stability of the target hydraulic cylinder when it enters the floating state.

[0146] S603. Based on the preset boom kinematic model, issue dead-point disengagement commands to the remaining unlocked joints;

[0147] Based on the preset boom kinematic model, dead-point disengagement commands are issued to the remaining unlocked joints, specifically including:

[0148] Obtain the preset boom kinematic model in the current spatial pose, and associate the remaining unlocked joints with the garbage container hook point using the Jacobian matrix. With maximizing the axial displacement of the piston rod of the target hydraulic cylinder as the optimization objective and with the spatial coordinate change of the garbage container hook point being less than the preset anti-shake threshold as the constraint, solve the zero-space motion solution of the Jacobian matrix. Transform the zero-space motion solution into the driving position increment of the remaining unlocked joints to generate a dead-point disengagement command.

[0149] The hook points of the garbage container include the physical contact points connecting the boom hook to the container and the lifting interface; the Jacobian matrix includes partial derivative matrices describing the mapping relationship between joint velocity and end effector velocity; the kinematic differential matrix includes piston rod axial displacements, such as cylinder extension / retraction length and linear motion distance; preset anti-shake thresholds include maximum permissible spatial position deviation and millimeter-level coordinate fluctuation limits, derived from the stability requirements of boom operation, serving as a safety limit for end effector position fluctuations; zero-space motion solutions include joint motion vectors that do not change the end effector pose and internal motion solutions for redundant degrees of freedom; drive position increments include joint angle adjustment steps and cylinder extension / retraction corrections; and dead-point release commands include micro-motion control signals and escape displacement messages. Issuing dead-point release commands utilizes the redundant degrees of freedom of the boom system to actively create an internal mechanical relative motion without affecting overall operational stability. By optimizing the zero-space motion solution, the motion trend of the target cylinder can be maximized while maintaining a relatively constant end effector position. This improves the system's motion planning capability under complex constraints and reduces the risk of the target hydraulic cylinder remaining stuck in a mechanical dead point for an extended period.

[0150] A gradient projection algorithm based on a pseudo-inverse matrix can be used to solve and generate commands. First, based on the preset boom kinematic model and the current joint angles, the Jacobian matrix relating the remaining unlocked joints to the garbage bin hook points is calculated. Next, an objective function is constructed to maximize the axial displacement of the piston rod, and the gradient vector of this objective function with respect to each joint variable is calculated. The null space projection matrix is ​​calculated using the pseudo-inverse of the Jacobian matrix, and the gradient vectors are projected into this null space to obtain the null space motion solution. During the projection process, the spatial coordinate changes of the garbage bin hook points are checked in real time; if they exceed a preset anti-shake threshold, the step size is reduced proportionally. Finally, the null space motion solution that satisfies the constraints is multiplied by the control cycle, transformed into the drive position increment of the remaining unlocked joints, and packaged to generate a dead-point release command.

[0151] This refined technical solution can also be implemented using a quadratic programming algorithm. Maximizing the axial displacement of the piston rod is transformed into a quadratic objective function, with the product of the Jacobian matrix and the joint velocity equal to zero used as an equality constraint to ensure zero-space motion characteristics. Simultaneously, the spatial coordinate change of the garbage bin hook point being less than a preset anti-shake threshold is transformed into an inequality constraint. These conditions are input into a quadratic programming solver for iterative optimization, solving for the optimal joint velocity vector as the zero-space motion solution. Subsequently, this velocity vector is discretized and integrated, transforming it into the drive position increments of each remaining unlocked joint, and then formatted and encoded to finally generate a dead-point disengagement command recognizable by the underlying actuator.

[0152] S604. Control the remaining unlocked joints to execute the dead point disengagement command to generate displacement, so as to drag the target hydraulic cylinder in the floating state away from the mechanical dead point through the linkage of the boom.

[0153] Linkage coupling includes physical traction between robotic arms, relative motion forces transmitted at hinge points, dragging (e.g., physical pulling, mechanical pushing), and deviation (e.g., leaving extreme positions, exiting dead zones). Controlling the remaining joints to execute commands is to translate the calculated numerical plan into actual physical actions. Because the target hydraulic cylinder is in a floating state, it cannot generate power itself and must rely on the movement of other joints to transmit force through rigid mechanical connections, forcibly changing its physical position. This improves the physical utilization rate of multi-joint collaborative operations and reduces the probability of the entire system failing due to a single joint becoming trapped.

[0154] A distributed servo control architecture can be used to execute displacement and generate drag. The central controller synchronously sends dead-point release commands to each local servo drive controlling the remaining unlocked joints via a high-speed fieldbus. Upon receiving the command, the servo drive's internal position and speed loops activate, driving the corresponding proportional directional valves to output precise hydraulic flow, causing the remaining unlocked joints to produce minute displacements according to the command. Because the folding boom sections are physically connected by high-strength hinge pins, these minute displacements combine in space, generating a strong linkage coupling effect. This mechanical coupling force acts directly on both ends of the target hydraulic cylinder in a floating state, overcoming its internal residual friction and physically dragging its piston rod, causing it to gradually deviate from the mechanical dead-point position.

[0155] Alternatively, a closed-loop control strategy based on master-slave synchronous following can be employed. In the control system, the remaining unlocked joint that executes the dead-point disengagement command is designated as the dominant motion axis, and its displacement is collected in real time as a reference. Based on the mechanical linkage geometry of the boom, the theoretically required following displacement of the target hydraulic cylinder when the dominant motion axis displaces is calculated. During the displacement generated by the remaining unlocked joint executing the command, the system continuously monitors the actual passive displacement of the target hydraulic cylinder and compares it with the theoretical following displacement. If lag is detected in the dragging process, the system dynamically fine-tunes the driving torque of the remaining unlocked joint to enhance the transmission efficiency of the linkage coupling, ensuring that the floating target hydraulic cylinder is dragged smoothly and effectively until it completely deviates from the mechanical dead point.

[0156] S605. When the target hydraulic cylinder is detected to be deviating from the mechanical dead point and its effective lever arm reaches the preset starting lever arm threshold, the floating state of the target hydraulic cylinder is terminated.

[0157] Effective lever arm includes, for example, the vertical distance between the hydraulic thrust and the joint rotation center, and the length of the torque transmission lever. Preset starting lever arm thresholds include, for example, the minimum safe driving lever arm and the initial ratio of the rated lever arm. These thresholds are derived from the product of the mechanical structure's geometric characteristics and the hydraulic cylinder's output force, serving as the lower spatial geometric limit for determining whether the cylinder has sufficient driving capacity to overcome the load. Ending the floating state is to regain control of the target hydraulic cylinder when the time is right. Near the mechanical dead point, the effective lever arm is extremely small, making it difficult to generate sufficient rotational torque even with a large hydraulic thrust, instead resulting in extremely high internal pressure. Waiting for the effective lever arm to reach the threshold before ending the floating state ensures that the cylinder can output sufficient torque at normal pressure during startup. This improves the energy conversion efficiency of the hydraulic system during restart and reduces the risk of system overflow, overheating, and mechanical damage caused by forcibly applying pressure when the lever arm is insufficient.

[0158] The floating state can be detected and terminated through real-time geometric calculations combined with sensor feedback. A high-precision linear displacement sensor is installed on the piston rod of the target hydraulic cylinder to collect the actual extension and retraction amount from the mechanical dead point in real time. This extension and retraction amount is input into a pre-established geometric trigonometric function model of the boom frame single joint to calculate in real time the vertical distance between the thrust direction of the target hydraulic cylinder and the joint rotation center, i.e., the effective lever arm. When the system confirms through the logic judgment module that the piston rod has made a substantial displacement from the mechanical dead point, and the calculated effective lever arm value is greater than or equal to the preset starting lever arm threshold, the central controller immediately sends a command to the solenoid directional valve controlling the cylinder to exit the floating position and restore normal working function, thereby ending the floating state of the target hydraulic cylinder.

[0159] This detection and control process can also be achieved using machine vision and image processing technologies. High-definition industrial cameras are installed in the key articulation areas of the boom to capture real-time motion images of the target hydraulic cylinder and its surrounding connecting rods. Edge detection algorithms and feature point matching techniques are used to extract the pixel coordinates of the cylinder axis and the joint rotation center from the images. Based on pre-calibrated camera intrinsic and extrinsic parameters, the pixel coordinates are converted into actual physical space coordinates, thereby calculating the length of the effective lever arm. Simultaneously, differential analysis of consecutive frames confirms that the piston rod of the target hydraulic cylinder has undergone relative displacement, deviating from the mechanical dead point. Once both conditions are met and the effective lever arm reaches the preset starting lever arm threshold, the system triggers an interrupt signal, controlling the hydraulic valve group to close the bypass unloading circuit and quickly ending the floating state of the target hydraulic cylinder.

[0160] S606. Restore the joint degrees of freedom corresponding to the target hydraulic cylinder in the preset boom kinematic model, and continue to generate control commands to maintain the target's stable hooking path based on the restored full-degree-of-freedom kinematic model.

[0161] Restoring joint degrees of freedom, such as reactivation or state reset, involves using fully free kinematic models, including complete Jacobian matrix models with all joint variables and unconstrained system dynamic equations. Restoring joint degrees of freedom and regenerating commands allows the boom system to return to its most ideal and efficient collaborative operating state. Once the target hydraulic cylinder is out of danger and has normal driving capability, the previous reduced-dimensional model is no longer applicable. Restoring full degrees of freedom fully utilizes the flexibility of the multi-joint system. This improves the trajectory tracking accuracy of the boom in subsequent hooking operations and reduces the problems of overall motion stiffness and low operating efficiency caused by the continuous restriction of some joints.

[0162] The model and commands can be reconstructed using matrix dimensionality increase and parameter reloading techniques. In the control system's software architecture, the joint variables of the previously removed or fixed target hydraulic cylinder are re-declared as active. The complete Jacobian matrix and homogeneous transformation matrix template backed up in system memory are extracted, and the current real-time angle and kinematic parameters of the target hydraulic cylinder are re-injected into the corresponding dimensions of the template, completing the matrix dimensionality increase operation and reconstructing a full-degree-of-freedom kinematic model. Subsequently, the desired end trajectory for maintaining the target's stable hooking path is used as input, and the inverse kinematics is iteratively solved using the reconstructed full-degree-of-freedom kinematic model. The desired angle or displacement of all joints, including the target hydraulic cylinder, in the next control cycle is calculated, converted into a standard control command sequence, and executed.

[0163] Alternatively, an adaptive control algorithm based on state machine switching can be used. A multi-state switching logic is constructed in the system's main control program. Upon receiving a flag indicating the target hydraulic cylinder has ended its floating state, the state machine automatically transitions from a reduced-dimensional constrained mode to a fully free-degree-of-freedom cooperative mode. At the moment of transition, the system calls an initialization function to reload the fully free-degree-of-freedom kinematic model containing all the complete physical parameters of the folding arm, using the current actual physical positions of each joint as the initial boundary conditions to eliminate potential numerical abrupt changes caused by model switching. Then, using an adaptive trajectory planning algorithm, guided by the target's smooth hooking path, the motion weights and velocity planning of each joint are redistributed within the fully free-degree-of-freedom space, generating smooth and continuous control commands. This ensures that the boom system can seamlessly connect and continue smoothly executing the hooking task after regaining full freedom of freedom.

[0164] In the above embodiments, by real-time monitoring of the equivalent load torque acting on the target hydraulic cylinder, when the torque drops to a preset recovery threshold, the cylinder is switched to a floating state that allows passive displacement. A dead-point disengagement command is then issued to the remaining unlocked joints. The linkage effect generated by the active displacement of the remaining joints pulls the target hydraulic cylinder away from the mechanical dead point. Once its effective lever arm reaches the starting threshold, the floating process ends and full-degree-of-freedom control is restored. This mechanism avoids direct load-bearing start-up of the target hydraulic cylinder at the mechanical dead point. It utilizes the mechanical linkage characteristics of the multi-section folding arm to achieve passive disengagement of the target joint, reducing the risk of instantaneous high-pressure impact and mechanical jamming caused by forcibly establishing hydraulic drive force at dead or limit points. This improves the reliability of the boom system's smooth transition from a rigid passive support state to a full-degree-of-freedom active control state and extends the service life of the hydraulic actuators.

[0165] The system in the embodiments of this invention is described below from the perspective of hardware processing. Please refer to [link / reference needed]. Figure 7 This is a schematic diagram of the physical device structure of a hook path planning system for a folding arm type garbage truck provided in an embodiment of this application.

[0166] It should be noted that, Figure 7 The structure of the system shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0167] like Figure 7As shown, the system includes a Central Processing Unit (CPU) 701, which can perform various appropriate actions and processes, such as executing the methods described in the above embodiments, based on a program stored in Read-Only Memory (ROM) 702 or a program loaded from storage portion 708 into Random Access Memory (RAM) 703. The RAM 703 also stores various programs and data required for system operation. The CPU 701, ROM 702, and RAM 703 are interconnected via a bus 704. An Input / Output (I / O) interface 705 is also connected to the bus 704.

[0168] The following components are connected to I / O interface 705: an input section 706 including a camera, infrared sensor, etc.; an output section 707 including a liquid crystal display (LCD) and speakers, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a LAN (Local Area Network) card and a modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to I / O interface 705 as needed. A removable medium 711, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 710 as needed so that computer programs read from it can be installed into storage section 708 as needed.

[0169] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing computer programs for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 709, and / or installed from removable medium 711. When the computer program is executed by central processing unit (CPU) 701, it performs the various functions defined in the present invention.

[0170] It should be noted that the computer-readable medium shown in the embodiments of the present invention can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, wherein a computer-readable computer program is carried. The transmitted data signal can take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof.

[0171] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0172] In another aspect, the present invention also provides a computer-readable storage medium, which may be included in the system described in the above embodiments; or it may exist independently and not assembled into the system. The storage medium carries one or more computer programs that, when executed by a processor of a system, cause the system to implement the methods provided in the above embodiments.

[0173] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0174] As used in the above embodiments, depending on the context, the term "when..." can be interpreted as "if...", "after...", "in response to determining...", or "in response to detecting...". Similarly, depending on the context, the phrase "when determining..." or "if (the stated condition or event) is interpreted as "if determining...", "in response to determining...", "when (the stated condition or event) is detected", or "in response to detecting (the stated condition or event)".

[0175] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive), etc.

[0176] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for planning the hooking path of a folding boom crane for garbage trucks, characterized in that, The boom arm includes a multi-section folding boom independently driven by multiple hydraulic cylinders, and the method includes: The system acquires the center of gravity offset data of the target garbage container and the current vehicle attitude tilt angle data, and combines them with the preset boom kinematic model to generate the initial joint motion trajectory that satisfies the end hook position constraint. Based on the initial hook trajectory and the preset boom dynamics model, calculate the load torque sequence of each folding arm under the initial hook trajectory; Traverse the load torque sequence, identify the trajectory segments where the torque change rate is greater than a preset torque change rate threshold as abrupt trajectory segments, and extract the target folding arm that generates a torque abrupt change within the abrupt trajectory segments; Calculate the target compensation torque required for the target folding arm to eliminate the torque abrupt change within the abrupt trajectory segment; Under the constraint of keeping the spatial trajectory of the hook at the end of the boom unchanged, based on the target compensation torque and the preset boom dynamic model, the joint compensation amount of other folding arms that move in coordination with the target folding arm is calculated using the redundant degrees of freedom of the multi-section folding arm. The joint compensation amount is integrated into the initial joint motion trajectory of each of the folding arms within the abrupt trajectory segment to reconstruct the target smooth hooking path. Control commands are output to each of the hydraulic cylinders according to the target smooth hooking path.

2. The method according to claim 1, characterized in that, Under the constraint of keeping the spatial trajectory of the hook at the end of the boom unchanged, based on the target compensation torque and the preset boom dynamic model, and utilizing the redundant degrees of freedom of the multi-section folding arm, the joint compensation of other folding arms that move in coordination with the target folding arm is calculated, specifically including: Based on the preset boom dynamics model, the redundant motion space that the other folding arms can perform is extracted without changing the spatial trajectory of the hook at the end of the boom. The dynamic load margin of the other folding arms in the current motion posture is obtained. The dynamic load margin is used to characterize the safety threshold that each of the other folding arms can withstand additional torque without overload. Based on the dynamic load margin, the target compensation torque is weighted and distributed within the redundant motion space to obtain the equivalent compensation torque shared by each of the other folding arms. Based on the equivalent compensation torque and the preset boom dynamic model, the joint compensation amount of the other folding arms is calculated in reverse.

3. The method according to claim 1, characterized in that, The step of fusing the joint compensation amount into the initial joint motion trajectory of each of the folding arms within the abrupt trajectory segment to reconstruct the target smooth hooking path specifically includes: The entry and exit nodes of the mutation trajectory segment in the initial joint motion trajectory are determined, and the initial motion state data of the initial joint motion trajectory at the entry and exit nodes are extracted. Based on the initial motion state data, a smooth transition function matching the two ends of the abrupt trajectory segment is constructed; The joint compensation amount is modulated in the time domain using the smooth transition function to obtain the modulated target joint compensation amount, so that the value and rate of change of the target joint compensation amount at the cut-in node and the cut-out node both tend to zero. The target joint compensation amount is superimposed onto the initial joint motion trajectory of each of the folding arms within the abrupt trajectory segment to reconstruct the target smooth hooking path.

4. The method according to claim 1, characterized in that, After outputting control commands to each of the hydraulic cylinders according to the target smooth hooking path, the method further includes: Obtain the real-time working pressure of each hydraulic cylinder when performing the joint compensation amount; If the real-time working pressure of the target hydraulic cylinder is continuously greater than the preset pressure threshold, it is determined that the garbage container has a large static off-center load. Under the constraint of keeping the current spatial position of the end hook point of the boom unchanged, the multi-section folding arm is controlled to perform redundant posture adjustments until the joint corresponding to the target hydraulic cylinder moves to the preset mechanical dead point position or the preset structural limit point. Lock the hydraulic circuit of the target hydraulic cylinder, so that the joint corresponding to the target hydraulic cylinder is switched from hydraulic drive to mechanical rigid support; The joint degrees of freedom corresponding to the target hydraulic cylinder are deleted from the preset boom kinematic model, and the control commands to maintain the smooth hooking path of the target are regenerated using the remaining unlocked joints.

5. The method according to claim 4, characterized in that, Under the constraint of keeping the current spatial position of the end hook point of the boom unchanged, the multi-section folding boom is controlled to perform redundant posture adjustments until the joint corresponding to the target hydraulic cylinder moves to a preset mechanical dead point or a preset structural limit point, specifically including: The target hydraulic cylinder is set as the main retraction actuator, and the other hydraulic cylinders in the multi-section folding arm, except for the target hydraulic cylinder, are set as driven compensation actuators. According to the preset safety step size, a fine-tuning displacement command is generated to make the main retraction actuator move unidirectionally to the preset mechanical dead point position or the preset structural limit point. Based on the preset boom kinematic model, calculate the virtual offset vector of the end hook point deviating from the current spatial position when the main retraction actuator executes the fine-tuning displacement command alone; With the goal of counteracting the virtual offset vector, synchronous compensation displacement commands corresponding to each of the driven compensation actuators are generated through inverse kinematics calculation. The fine-tuning displacement command and the synchronous compensation displacement command are issued and executed synchronously as a linkage control cycle, and the process returns to the step of setting the target hydraulic cylinder as the main retraction actuator until the main retraction actuator reaches the preset mechanical dead point position or the preset structural limit point.

6. The method according to claim 4, characterized in that, After regenerating the control commands to maintain the smooth hooking path of the target using the remaining unlocked joints, the method further includes: Real-time monitoring of the equivalent load torque acting on the target hydraulic cylinder by the boom in the current spatial orientation; When the equivalent load torque drops to a preset recovery threshold, the hydraulic circuit of the target hydraulic cylinder is switched to a floating state that allows passive displacement of the piston rod. Based on the preset boom kinematic model, a dead-point disengagement command is issued to the remaining unlocked joints; The remaining unlocked joints are controlled to execute the dead-point disengagement command to generate displacement, so as to drag the target hydraulic cylinder in the floating state away from the mechanical dead point through the linkage of the boom frame; When it is detected that the target hydraulic cylinder deviates from the mechanical dead point and its effective lever arm reaches the preset starting lever arm threshold, the floating state of the target hydraulic cylinder ends. The joint degrees of freedom corresponding to the target hydraulic cylinder are restored in the preset boom kinematic model, and control commands to maintain the smooth hooking path of the target are generated based on the restored full-degree-of-freedom kinematic model.

7. The method according to claim 6, characterized in that, The step of issuing dead-point disengagement commands to the remaining unlocked joints based on the preset boom kinematic model specifically includes: Obtain the preset boom kinematic model in the current spatial pose and associate the remaining unlocked joints with the garbage bin hook points using the Jacobian matrix. The optimization objective is to maximize the axial displacement of the piston rod of the target hydraulic cylinder, and the constraint is that the change in the spatial coordinates of the hook point of the garbage container is less than a preset anti-shaking threshold. The zero-space motion solution of the Jacobian matrix is ​​then solved. The zero-space motion solution is converted into the driving position increment of the remaining unlocked joints, generating a dead-point disengagement command.

8. A hook path planning system for a folding boom type garbage truck, characterized in that, The system includes: One or more processors and a memory; the memory is coupled to the one or more processors, the memory being used to store computer program code, the computer program code including computer instructions, the one or more processors invoking the computer instructions to cause the system to perform the method as described in any one of claims 1-7.

9. A computer-readable storage medium comprising instructions, characterized in that, When the instructions are executed on the system, the system performs the method as described in any one of claims 1-7.

10. A computer program product, characterized in that, When the computer program product is run on the system, the system performs the method as described in any one of claims 1-7.

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