Method for controlling a mechanical arm of vertical multi-joint series structure

Abstract

The application relates to the technical field of industrial robot control, in particular to a mechanical arm control method of a vertical multi-joint series structure, and the technical scheme points comprise the following steps: S1, system initialization and mode configuration, in response to a system power-on or reset instruction, a system initialization task is executed; S2, an equipment state management model based on a PackML standard is established, a state set of the equipment and a state conversion rule are defined; according to a current operation mode and a user instruction, the equipment is controlled to be sequentially converted among states; S3, dynamic step sequence planning of multi-axis motion track, target parameters of a stacking operation are acquired, and in a step sequence execution process, the execution progress of the current step sequence and the inter-axis coordination relationship are dynamically adjusted according to the feedback of real-time position states of the axes and external condition signals; the dynamic step sequence scheduling of the multi-axis coordinated motion optimizes the motion track and improves the stacking efficiency.

Description

Technical Field

[0001] This invention relates to the field of industrial robot control technology, specifically to a control method for a robotic arm with a vertical multi-joint serial structure. Background Technology

[0002] Vertical multi-joint serial structure robotic arms are one of the most common configurations in industrial robots. They achieve flexible movement of the end effector in three-dimensional space through multiple rotary joints connected in series. This type of robotic arm is widely used in industrial scenarios such as palletizing, handling, and assembly.

[0003] Trajectory planning for multi-axis coordinated motion is inefficient. Traditional control methods involve independent motion planning for each joint axis, lacking a coordinated scheduling mechanism between axes. In palletizing operations, the robotic arm needs to frequently reciprocate between the pick-up and drop-off points. Existing methods often employ a serial execution approach, where one axis completes its movement before the next begins, resulting in long cycle times and low production efficiency. Some solutions use five-axis linkage forward and inverse kinematics algorithms to achieve multi-axis coordination, but their trajectory planning lacks a flexible step sequence scheduling mechanism, making it difficult to adapt to complex and ever-changing palletizing requirements.

[0004] Existing control systems manage equipment operating status in a rather crude manner, lacking refined state definitions and state transition control. When abnormal situations such as alarms or emergency stops occur, the system often shuts down directly, lacking orderly state transition processes such as stopping, pausing, and resuming. Summary of the Invention

[0005] To address the technical problems and shortcomings of existing technologies, this invention provides a control method for a robotic arm with a vertical multi-joint serial structure, which enables dynamic step sequence scheduling of multi-axis coordinated motion, optimizes motion trajectory, and improves palletizing efficiency.

[0006] To achieve the above and other related objectives, the present invention adopts the following technical solution:

[0007] A control method for a robotic arm with a vertical multi-joint serial structure, characterized by comprising the following steps:

[0008] Step S1: System initialization and mode configuration, in response to system power-on or reset commands, execute system initialization tasks;

[0009] Step S2: Establish a device state management model based on the PackML standard, defining the device's state set and state transition rules; the state set includes Idle, Starting, Execute, Completing, Complete, Stopping, Stopped, Aborting, Aborted, Resetting, Suspending, Suspended, Unsuspending, Holding, Held, Unholding, and Clearing; control the device to transition between states in an orderly manner according to the current operating mode and user instructions;

[0010] Step S3: Dynamic step sequence planning for multi-axis motion trajectories. Obtain the target parameters for the palletizing operation, including at least the number of palletizing rows, columns, layers, and material size parameters. Generate a step sequence for the motion trajectory based on the target parameters. Each step sequence defines the target position, motion speed, acceleration / deceleration parameters, and inter-axis priority for each motion axis. During step sequence execution, dynamically adjust the execution progress and inter-axis coordination based on the real-time position status of each axis and feedback from external condition signals. This includes:

[0011] Assign an execution priority to each motion axis in each step sequence, with the axis with the higher priority starting its motion first;

[0012] For multiple axes with the same priority, a synchronous start method is used to enable multiple axes to start moving simultaneously;

[0013] Based on the completion status of the previous axis's motion, trigger the start of motion on the next priority axis;

[0014] When switching steps, check if all conditions of the current step are met. If they are met, proceed to the next step. If they are not met, wait for the conditions to be met or perform a skip step operation.

[0015] Preferably, the "dynamically adjusting the execution progress of the current step sequence" in step S3 includes a step sequence jump mechanism: when it is detected that the execution conditions of the current step sequence are not met and it is predicted that the conditions cannot be met within a preset time, some or all of the motion instructions of the current step sequence are skipped, and the next step sequence is executed directly; the step sequence jump mechanism is applied to at least the following scenarios:

[0016] (a) When the material sensing signal indicates that there is no material at the material picking position, skip the material picking step and directly execute the standby step;

[0017] (b) When the feeding position is occupied, skip the feeding step and execute the waiting step;

[0018] (c) When the pallet is full, skip the current palletizing step and perform the pallet change step.

[0019] By adding a step-skipping mechanism, the system gains adaptive adjustment capabilities. When external conditions change (such as material shortage, blockage, or a full pallet), the system can skip unnecessary steps, avoiding ineffective movements. This mechanism, combined with dynamic step scheduling, allows the robotic arm to flexibly adjust its workflow based on real-time conditions, maintaining high operating efficiency even under less than ideal conditions.

[0020] Preferably, the state transition rules in step S2 specifically include:

[0021] (a) After receiving the start command, the idle state transitions to the starting state; after completing the initialization preparations in the starting state, it automatically transitions to the execution state.

[0022] (b) After receiving a stop command, the Execute state transitions to the Stopping state; after the Stopping state completes the axis stop and saves the status, it automatically transitions to the Stopped state.

[0023] (c) After receiving a pause command, the Execute state transitions to the Suspending state; after completing motion pause and state saving in the Suspending state, it automatically transitions to the Suspended state; after receiving a resume command, the Suspended state transitions to the Unsuspending state, and then automatically resumes to the Execute state.

[0024] (d) When the Execute state receives an abort command or detects a serious alarm, it transitions to the Aborting state; after completing the emergency stop and fault recording in the Aborting state, it automatically transitions to the Aborted state; after receiving a reset command, the Aborted state transitions to the Resetting state, and after the reset is completed, it automatically transitions to the Idle state.

[0025] (e) If an emergency stop signal is detected in any state, immediately switch to the aborting state.

[0026] Preferably, step S4 is also included: during the palletizing operation, multi-level safety protection tasks are executed in parallel, including:

[0027] Soft limit protection layer: The real-time position of each motion axis is obtained and compared with the preset positive soft limit and reverse soft limit. If the limit range is exceeded, an alarm is triggered and the motion of the axis is stopped.

[0028] Torque collision detection layer: acquires the real-time torque value of each motion axis, compares the real-time torque value with the preset no-load torque threshold and full-load torque threshold, and if the threshold is exceeded, triggers a collision alarm and stops the movement of the corresponding axis;

[0029] Emergency stop linkage layer: Real-time monitoring of the status of emergency stop signals and anti-collision sensing signals. If an emergency stop signal or anti-collision sensing signal is detected, the operation of all motion axes and associated equipment will be stopped immediately.

[0030] Cylinder status monitoring layer: Real-time monitoring of the original position signal and moving position signal of each cylinder. If the target position signal is not detected within a preset time, a cylinder position timeout alarm is triggered.

[0031] Preferably, the soft-limiting protective layer in step S4 further includes a dynamic soft-limiting adjustment mechanism:

[0032] The soft limit range is automatically adjusted according to the current operating mode of the robotic arm: in manual mode, the first soft limit range is used, which is smaller than the hard limit stroke of the robotic arm; in production mode, the second soft limit range is used, which is larger than the first soft limit range but smaller than the hard limit stroke.

[0033] When the axis position is detected to be close to the soft limit boundary, the movement speed of the axis is automatically reduced; when the axis position exceeds the soft limit range, an alarm is triggered and the movement of the axis is stopped.

[0034] This solution specifies the state transition rules, particularly defining the pause / resume mechanism (rule c) and the tiered stop mechanism (the distinction between rules b and d). The pause mechanism allows equipment to temporarily interrupt operations and quickly resume without shutting down, while the stop mechanism handles severe faults. This tiered handling is linked to step S4: minor anomalies trigger pause, and severe faults trigger stop. This tiered response ensures safety while minimizing production losses in abnormal situations. Different limit ranges are used in different modes—stricter limits in manual mode (debugging scenario) to protect equipment and personnel, and appropriately relaxed limits in production mode (normal operation scenario) to fully utilize workspace. This mechanism, along with step S1 and torque collision detection, forms a multi-layered protection: soft limits act as the first line of defense against overtravel, and torque detection acts as the second line of defense against collisions.

[0035] Preferably, the torque collision detection layer in step S4 further includes an idle torque self-learning mechanism: when the robotic arm is powered on for the first time or during periodic maintenance, an idle torque self-learning step is executed: each motion axis is controlled to reciprocate at a preset speed within a preset stroke range, the torque value of each axis at different positions is recorded, and an idle torque reference curve is established; during actual operation, the real-time torque value is compared with the idle torque reference curve, and if the real-time torque value exceeds the preset multiple of the idle torque reference value, it is determined that a collision has occurred and a collision alarm is triggered; the preset multiple is set according to the type of axis, and the preset multiple of the Z-axis is less than the preset multiples of the X-axis and Y-axis.

[0036] This solution establishes a no-load torque reference curve instead of using a fixed threshold, enabling the system to adapt to normal torque fluctuations under different mechanical conditions (such as changes in lubrication conditions and mechanical wear), thus reducing false alarms. Simultaneously, a smaller multiplier threshold is used for the Z-axis (because the Z-axis is responsible for lifting and lowering, and the consequences of a collision are more severe), reflecting a differentiated safety strategy. This mechanism, combined with step S4, improves the accuracy and reliability of collision detection.

[0037] Preferably, step S1 involves system initialization tasks, including: an input task to acquire the status of external input signals, a communication task to establish communication connections with the host computer and slave devices, and a system diagnostic task to detect the health status of each hardware module; configuring the system operating mode, which includes at least a production mode, a manual mode, and an initialization mode; wherein, the initialization mode is used for axis return and parameter initialization after the system is first powered on or reset, the manual mode is used for manual debugging and point-to-point debugging, and the production mode is used for executing automatic palletizing operations.

[0038] Preferably, the method further includes an event management and alarm classification mechanism:

[0039] Define event priority levels, which include at least emergency events, warning events, and information events;

[0040] Map various abnormal situations to their corresponding event priority levels:

[0041] Emergency stop triggering, servo failure, and collision detection triggering are classified as emergency events, and the termination process is executed immediately upon triggering.

[0042] Material shortage timeout, cylinder positioning timeout, and conveyor belt running timeout are classified as warning events. After being triggered, the alarm information is recorded and the current status is maintained for manual confirmation.

[0043] Device status changes, step completion, etc. are classified as information events and are only used for status display and log recording;

[0044] When multiple events occur simultaneously, they are processed in descending order of priority. Warning events are automatically cleared if they are not acknowledged within a preset time and the conditions have been restored after being triggered.

[0045] In this solution, emergency events trigger the state machine's termination process, warning events trigger the pause process, and information events are only logged. This hierarchical processing, in conjunction with the state transition rules, forms a complete closed loop from event detection to state response and action execution. Prioritization and automatic clearing mechanisms prevent the accumulation of alarm information and the impact of false alarms on production.

[0046] Preferably, the system initialization task in step S1 further includes axis enable management and parameter initialization: during the system initialization phase, enable commands are sent to the servo drivers of each motion axis to make each axis operable; motion parameters are configured for each motion axis, the motion parameters including at least acceleration, deceleration, and jog speed; speed multipliers are set according to the operating mode: in production mode, the motion speed of each axis is adjusted according to a preset automatic speed multiplier; in manual mode, the jog speed of each axis is adjusted according to a preset jog speed multiplier; the speed multiplier ranges from 0 to 1, and when the speed multiplier exceeds this range, it is automatically corrected to the default value.

[0047] This scheme avoids abnormal motion caused by improper parameter settings by limiting the speed multiplier between 0 and 1 and automatically correcting it. This mechanism is combined with mode configuration (step S1) and step sequence planning (step S3): different speed multipliers are applied in different modes, and the multiplier value directly affects the motion speed parameters of each axis in the step sequence, realizing a complete parameter transfer chain from mode selection to parameter configuration to motion execution.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] 1. This invention adopts a state management model based on the PackML standard, which divides device control into multiple standardized modules such as input tasks, communication tasks, system diagnostics, interface tasks, and output mapping. Each module has a clear function and low coupling, which facilitates system maintenance, expansion and cross-platform portability.

[0050] 2. This invention achieves priority-based coordinated motion of multiple axes through a dynamic step sequence scheduling mechanism. Compared with the traditional serial control method, the X and Y axes can move synchronously, and the Z axis can move earlier or later according to the priority strategy, which greatly reduces the palletizing cycle time.

[0051] 3. This invention defines 17 standard states and complete state transition rules, realizing full-process state management from normal production to anomaly handling and recovery. When an alarm or emergency stop occurs, the system stops in an orderly manner according to the predefined state transition path, avoiding equipment damage and data loss caused by disordered shutdown.

[0052] Other additional advantages and benefits of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0053] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0054] Figure 1 This is a schematic diagram of the overall structure of the robotic arm with a multi-joint serial structure according to an embodiment of this application.

[0055] Explanation of reference numerals for major components:

[0056] 1. Joint One; 2. Joint Two; 3. Joint Three; 4. Joint Four; 5. Joint Five. Detailed Implementation

[0057] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. The following specific examples illustrate the embodiments of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0058] refer to Figure 1 The example robotic arm features a multi-joint serial structure, with joints 1, 2, 3, 4, and 5 connected vertically from top to bottom, achieving a vertical distribution. In other robotic arms, the term "joint" in this field refers to the joint motor, specifically used on the robotic arm; more specifically, in terms of control, we simplify it to multi-axis control, which refers to controlling the motion axes. In this embodiment, the specific method involves controlling the motion axes of the joint motors.

[0059] Example:

[0060] Regarding: System Initialization and Mode Configuration. Upon system power-up, the initialization task sequence is executed first. The input task (SBR_PRG_0_INPUT) acquires the status of all external input signals, including emergency stop signals, sensor signals, and button signals. The communication task (SBR_PRG_1_COMMUNICATION) establishes communication connections with the host computer, servo drives, remote slave stations, and other devices. The system diagnostic task (SBR_PRG_2_SYSDIAG) checks the health status of each hardware module, including servo drive status, communication status, and I / O module status. The device unit interface task (SBR_PRG_3_INTERFACE) is called during master station startup or simulation mode for data interaction with the master station. The output mapping task (SBR_PRG_4_OUTPUT) maps control commands to physical output points, and the input mapping task maps physical input points to control variables.

[0061] The system operating mode can be configured via host computer commands or the local operation panel. Production mode is used to perform automatic palletizing operations, manual mode is used for manual debugging and point teaching, and initialization mode is used for axis return and parameter initialization after the system is first powered on or reset.

[0062] In manual mode, operators can perform jog control on each axis via a teach pendant or control panel, and can record and modify key position parameters such as standby position, pick-up position, and unload position. In production mode, the system automatically executes a palletizing cycle according to preset palletizing parameters.

[0063] Regarding state management based on the PackML standard: This invention adopts a state management model based on the PackML standard. The state machine defines 17 standard states, and the transitions between states follow predefined rules. The Idle state is the initial state of the system. In this state, the device has completed initialization but has not yet started production. When a start command is received (UN_stCmd.xAutoStart is TRUE) and the system is currently in manual mode or execution state, the system transitions to the Starting state.

[0064] The Start-up state performs pre-production preparations. For the robotic arm unit, the Start-up state executes operations such as axis return to the home position, cylinder initialization, and palletizing parameter initialization. Specifically, this includes: the Z-axis first returns to the standby position height, then the X and Y axes simultaneously return to the standby position, and the gripper cylinders open to their positions. Once all preparations are complete, the system automatically transitions to the Execute state.

[0065] The Execute state is the core production state. In this state, the robotic arm cyclically performs palletizing operations according to a preset sequence of steps. The specific steps include: moving from the standby position to the picking position → descending to the picking height → gripping with the grippers → rising to the picking height → moving to the unloading position → descending to the unloading height → releasing with the grippers → rising to the unloading height → returning to the standby position. The execution progress of each step is dynamically controlled by the step sequence scheduler.

[0066] When a stop command is received (UN_stCmd.xAutoStop is TRUE), the system transitions from the running state to the stopping state. In the stopping state, the system stops all motion axes, saves the current step sequence progress (for subsequent recovery), and then transitions to the stopped state.

[0067] When a pause command is received (UN_stCmd.xAutoHalt is TRUE), the system transitions from the running state to the suspending state. In the suspending state, the system pauses its movement after completing the current step sequence, saves its state, and then transitions to the suspended state. When the pause command is released, the system returns to the running state via the unsuspending state.

[0068] When a critical alarm (such as servo failure, collision detection) or emergency stop signal is detected, the system immediately transitions to the aborting state. In the aborting state, the system performs an emergency stop, records fault information, and then transitions to the aborted state. After the fault is cleared, the system returns to the idle state via the reset command (UN_stCmd.xResetAlarm).

[0069] Regarding dynamic step sequence planning for multi-axis motion trajectories, this invention employs a step sequence table for trajectory planning. The step sequence table defines the target position, motion speed, acceleration / deceleration parameters, and inter-axis priority for each axis in each step sequence. Taking a typical palletizing cycle as an example, the step sequence table is defined as follows: Step 0 (Standby Position Return): The Z-axis prioritizes returning to the standby position height, while the X and Y axes synchronously return to the standby position plane. Priority is set as follows: Z-axis priority is 0 (highest), and X and Y-axis priorities are 1.

[0070] Step 1 (Proceed to Pickup Position): The X and Y axes move synchronously to the pickup position on the plane, while the Z axis moves to the higher pickup position (Z coordinate of pickup position + material lifting height). The priority is set as 0 for the X and Y axes and 1 for the Z axis.

[0071] Step 2 (Descending to Pick Up Material): The Z-axis descends from the high position to the Z-coordinate of the picking position. This step is executed only after Step 1 is completed. Upon reaching the picking position, the picking conditions are checked (material arrival signal is valid). If the conditions are met, the gripper clamping action is triggered.

[0072] Step 3 (Rise to high pick-up position): The Z-axis rises from the pick-up position to the high pick-up position.

[0073] Step 4 (Proceed to the Unloading Position): The X and Y axes move synchronously to the unloading position on the plane, and the Z axis moves to the unloading height (unloading position Z coordinate + material lifting height). The unloading position coordinates are dynamically calculated based on the current row, column, and layer numbers of the pallet.

[0074] Step 5 (Lowering and Unloading): The Z-axis descends from the unloading high position to the unloading position Z-coordinate. Upon reaching the unloading position, the gripper release action is triggered.

[0075] Step 6 (Rise to High Discharge Position): The Z-axis rises from the discharge position to the high discharge position, and then returns to step 0 to start the next cycle.

[0076] During the step sequence execution, the step sequence scheduler monitors the position status of each axis in real time. When all axes of the same priority have reached the target position and stabilized within the position tolerance range, the movement of the next priority axis is triggered. The position tolerance for the X and Y axes is set to ±0.5mm, and the position tolerance for the Z axis is set to ±0.2mm.

[0077] This invention constructs a four-layer safety protection system. The first layer is soft limit protection. Positive soft limits and reverse soft limits are set for the X-axis, Y-axis and Z-axis respectively. Taking the X-axis as an example, the positive soft limit is set to U0_EM0_arLimitPos_X[0] and the reverse soft limit is set to U0_EM0_arLimitPos_X[1]. During the movement, the soft limit function block (afbSetLimit) monitors the axis position in real time. When the position exceeds the limit range, an alarm (xAlarmFor or xAlarmRev) is triggered and the axis movement is stopped. In manual mode, the soft limit range is narrowed to provide higher safety; in production mode, the soft limit range is appropriately widened to make full use of the workspace. The second layer is torque collision detection. The real-time torque value (rStsAxisTrq) of the servo drive is read and compared with the preset no-load torque threshold (Panle_arLimitTrq_NOLoad) and full-load torque threshold (Panle_arLimitTrq_AllLoad). When the torque value exceeds the no-load threshold, a no-load collision warning is triggered (applicable to collision detection in scenarios where the machine is running under load after material removal); when the torque value exceeds the full-load threshold, a full-load collision warning is triggered (applicable to severe collision detection in scenarios where the machine is running under load after material removal). The collision detection enable signal (Panle_axEnableTrqAlarm) is used to temporarily disable torque detection under specific operating conditions (such as torque fluctuations at startup). The third layer is emergency stop linkage. The emergency stop signal (IO_xEmergencyStop) is connected to the hardware emergency stop circuit and also serves as the highest priority interrupt signal at the software level. When the emergency stop signal is triggered, all moving axes stop immediately, all cylinders return to the safe position, and all frequency converters stop running. The anti-collision sensing signal (IO_xAnti-collision Sensing) serves as an auxiliary safety signal. When anti-collision sensing is detected and not disabled (Panle_x Anti-collision Disabling is FALSE), it also triggers emergency stop linkage. The fourth layer is cylinder status monitoring. Each cylinder is equipped with an in-situ sensor and a moving position sensor. After issuing an action command, the cylinder control function block (afbCylctrl) monitors the target position's arrival signal. If no arrival signal is detected within a preset time (diSetAlarmTime), a cylinder arrival timeout alarm is triggered. For example, after issuing a clamping command, if the gripper cylinder does not detect a movement signal (IO_x gripper moving point) within a set time, an alarm is triggered (U0_EM0_astCylHmi[gripper cylinder].xStsAlarmRight).

[0078] The step sequence scheduler also supports conditional jumps. For example, when there is no material at the pick-up position (the pick-up sensor signal is invalid), the system skips steps 1 and 2 and directly executes step 3 and subsequent steps to avoid invalid movements. When the unloading position is occupied (the unloading sensor signal is valid but the tray is not in place), the system pauses the execution of step 4 and waits for the unloading conditions to be met.

[0079] The event management mechanism of this invention performs hierarchical processing for various abnormal situations.

[0080] Emergency events include: emergency stop trigger (axEventStatus[0]), X-axis servo failure (axEventStatus[6]), Y-axis servo failure (axEventStatus[7]), Z-axis servo failure (axEventStatus[8]), X-axis torque collision (axEventStatus

[30] ), Y-axis torque collision (axEventStatus

[31] ), Z-axis torque collision (axEventStatus

[32] ), etc. After an emergency event is triggered, the system immediately executes the abort procedure and stops all motion.

[0081] Warning events include: long waiting time warning (axEventStatus

[22] ), material blockage warning (axEventStatus

[20] ), conveyor frequency converter operation timeout (axEventStatus

[16] ), buffer conveyor frequency converter operation timeout (axEventStatus

[17] ), fork angle rise timeout (axEventStatus

[18] ), fork angle fall timeout (axEventStatus

[19] ), etc. After a warning event is triggered, the system records the alarm information and maintains the current state, waiting for manual confirmation or automatic recovery.

[0082] Information events include: device status changes, step sequence completion, etc., which are only used for status display and log recording and do not trigger any actions.

[0083] When multiple events occur simultaneously, the system processes them sequentially in descending order of priority. Warning events are automatically cleared if they are not acknowledged within a preset time and the triggering conditions have been resolved, thus preventing alarm backlog.

[0084] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for a robotic arm with a vertical multi-joint serial structure, characterized in that, Includes the following steps: Step S1: System initialization and mode configuration, in response to system power-on or reset commands, execute system initialization tasks; Step S2: Establish a device state management model based on the PackML standard, defining the device's state set and state transition rules; the state set includes Idle, Starting, Execute, Completing, Complete, Stopping, Stopped, Aborting, Aborted, Resetting, Suspending, Suspended, Unsuspending, Holding, Held, Unholding, and Clearing; control the device to transition between states in an orderly manner according to the current operating mode and user instructions; Step S3: Dynamic step sequence planning for multi-axis motion trajectory, obtaining target parameters for palletizing operation, the target parameters including at least the number of palletizing rows, columns, layers and material size parameters; generating a step sequence sequence for motion trajectory based on the target parameters, each step sequence defining the target position, motion speed, acceleration / deceleration parameters and inter-axis priority of each motion axis; During step sequence execution, the execution progress and inter-axis coordination are dynamically adjusted based on the real-time position status of each axis and feedback from external condition signals; including: Assign an execution priority to each motion axis in each step sequence, with the axis with the higher priority starting its motion first; For multiple axes with the same priority, a synchronous start method is used to enable multiple axes to start moving simultaneously; Based on the completion status of the previous axis's motion, trigger the start of motion on the next priority axis; When switching steps, check if all conditions of the current step are met. If they are met, proceed to the next step. If they are not met, wait for the conditions to be met or perform a skip step operation.

2. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 1, characterized in that, The "dynamically adjusting the execution progress of the current step sequence" mentioned in step S3 includes a step sequence jump mechanism: When it is detected that the execution conditions of the current step sequence are not met and it is predicted that the conditions cannot be met within a preset time, skip some or all of the motion instructions of the current step sequence and directly execute the next step sequence. The step jump mechanism is applicable to at least the following scenarios: (a) When the material sensing signal indicates that there is no material at the material picking position, skip the picking step and directly execute the standby step; (b) When the feeding position is occupied, skip the feeding step and execute the waiting step; (c) When the pallet is full, skip the current palletizing step and perform the pallet change step.

3. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 1, characterized in that, The state transition rules mentioned in step S2 specifically include: (a) After receiving the start command, the idle state transitions to the starting state; after completing the initialization preparations in the starting state, it automatically transitions to the execution state. (b) After receiving a stop command, the Execute state transitions to the Stopping state; after the Stopping state completes the axis stop and saves the status, it automatically transitions to the Stopped state. (c) After receiving a pause command, the Execute state transitions to the Suspending state; after completing motion pause and state saving in the Suspending state, it automatically transitions to the Suspended state; after receiving a resume command, the Suspended state transitions to the Unsuspending state, and then automatically resumes to the Execute state. (d) When the Execute state receives an abort command or detects a serious alarm, it transitions to the Aborting state; after completing the emergency stop and fault recording in the Aborting state, it automatically transitions to the Aborted state; after receiving a reset command, the Aborted state transitions to the Resetting state, and after the reset is completed, it automatically transitions to the Idle state. (e) If an emergency stop signal is detected in any state, immediately switch to the aborting state.

4. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 1, characterized in that, It also includes step S4: During the palletizing operation, multi-level safety protection tasks are executed in parallel, including: Soft limit protection layer: The real-time position of each motion axis is obtained and compared with the preset positive soft limit and reverse soft limit. If the limit range is exceeded, an alarm is triggered and the motion of the axis is stopped. Torque collision detection layer: acquires the real-time torque value of each motion axis, compares the real-time torque value with the preset no-load torque threshold and full-load torque threshold, and if the threshold is exceeded, triggers a collision alarm and stops the movement of the corresponding axis; Emergency stop linkage layer: Real-time monitoring of the status of emergency stop signals and anti-collision sensing signals. If an emergency stop signal or anti-collision sensing signal is detected, the operation of all motion axes and associated equipment will be stopped immediately. Cylinder status monitoring layer: Real-time monitoring of the original position signal and moving position signal of each cylinder. If the target position signal is not detected within a preset time, a cylinder position timeout alarm is triggered.

5. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 4, characterized in that, The soft limit protection layer described in step S4 also includes a dynamic soft limit adjustment mechanism: The soft limit range is automatically adjusted according to the current operating mode of the robotic arm: in manual mode, the first soft limit range is used, which is smaller than the hard limit stroke of the robotic arm; in production mode, the second soft limit range is used, which is larger than the first soft limit range but smaller than the hard limit stroke. When the axis position is detected to be close to the soft limit boundary, the movement speed of the axis is automatically reduced; when the axis position exceeds the soft limit range, an alarm is triggered and the movement of the axis is stopped.

6. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 5, characterized in that, The torque collision detection layer described in step S4 also includes an idle torque self-learning mechanism: When the robotic arm is powered on for the first time or during regular maintenance, a no-load torque self-learning step is performed: control each motion axis to reciprocate at a preset speed within a preset stroke range, record the torque value of each axis at different positions, and establish a no-load torque reference curve. During actual operation, the real-time torque value is compared with the no-load torque reference curve. If the real-time torque value exceeds the preset multiple of the no-load torque reference value, it is determined that a collision has occurred and a collision alarm is triggered. The preset magnification is set according to the type of axis, with the preset magnification of the Z-axis being less than that of the X-axis and Y-axis.

7. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 1, characterized in that, Step S1 involves system initialization tasks, including: input tasks to acquire external input signal status, communication tasks to establish communication connections with the host computer and slave devices, and system diagnostic tasks to detect the health status of each hardware module; configuring system operating modes, which include at least production mode, manual mode, and initialization mode; wherein, the initialization mode is used for axis return and parameter initialization after the system is first powered on or reset, the manual mode is used for manual debugging and point-to-point debugging, and the production mode is used to perform automatic palletizing operations.

8. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 1, characterized in that, The method also includes an event management and alarm classification mechanism: Define event priority levels, which include at least emergency events, warning events, and information events; Map various abnormal situations to their corresponding event priority levels: Emergency stop triggering, servo failure, and collision detection triggering are classified as emergency events, and the termination process is executed immediately upon triggering. Material shortage timeout, cylinder positioning timeout, and conveyor belt running timeout are classified as warning events. After being triggered, the alarm information is recorded and the current status is maintained for manual confirmation. Device status changes, step completion, etc. are classified as information events and are only used for status display and log recording; When multiple events occur simultaneously, they are processed in descending order of priority. Warning events are automatically cleared if they are not acknowledged within a preset time and the conditions have been restored after being triggered.

9. The control method for a robotic arm with a vertical multi-joint serial structure according to claim 1, characterized in that, The system initialization task in step S1 also includes axis enable management and parameter initialization: During the system initialization phase, enable commands are sent to the servo drivers of each motion axis to bring each axis into an operable state. Configure motion parameters for each motion axis, wherein the motion parameters include at least acceleration, deceleration and jogging speed; Set the speed ratio according to the operating mode: In production mode, adjust the movement speed of each axis according to the preset automatic speed ratio; In manual mode, the jog speed of each axis is adjusted according to the preset jog speed ratio; The speed multiplier ranges from 0 to 1. When the speed multiplier exceeds this range, it is automatically corrected to the default value.

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