Online fixed-point assembly method and system for bottom-mounted battery pack of new energy truck

Abstract

The application provides a new energy truck bottom-mounted battery pack online fixed-point assembling method and system. The method comprises the following steps: transferring the battery pack from the buffer area to the line-side intermediate station beside the assembling line, positioning and adjusting the multi-degree-of-freedom attitude of the battery pack, so that the battery pack is in the target position and attitude for assembling; bearing the vehicle frame assembly and making it run along the assembling line, and stopping the electric vehicle at the assembling station; assembling the adjusted battery pack to the vehicle frame assembly; after the assembling is completed, the transfer AGV is controlled to run at a chasing speed higher than the normal speed, so that the production line rhythm is restored to the preset rhythm. Through the design of the pre-treatment, fixed-point stop assembling and accelerated chasing rhythm, the attitude of the battery pack is adjusted in advance to ensure readiness, the fixed-point stop ensures the static assembling precision and safety, and the accelerated chasing dynamically digests the stop time after assembling, so that the technical problems that the assembling precision and production efficiency cannot be considered simultaneously are solved.

Description

Technical Field

[0001] This invention relates to the field of intelligent manufacturing and automated assembly technology for new energy vehicles, specifically to an online fixed-point assembly method and system for under-mounted battery packs in new energy trucks. Background Technology

[0002] With the rapid development of the new energy vehicle industry, new energy trucks, as an important branch of the commercial vehicle sector, have battery pack assembly efficiency and precision that directly affect the production cycle and quality of the entire vehicle. Currently, most new energy truck battery packs adopt a bottom-mounted arrangement, meaning the battery pack is installed below the longitudinal beams of the chassis. This structure helps to lower the vehicle's center of gravity and improve driving stability, but it also places higher demands on assembly precision and ease of operation. In existing technologies, the following solutions are mainly used for the assembly of under-mounted battery packs for new energy trucks: Solution 1: After the new energy truck chassis is unpowered and trailer-mounted, the chassis is lifted using a rework lifting device, and the battery pack is statically assembled offline outside the production line; Solution 2: Multiple battery packs are lifted multiple times at a fixed workstation on the production line using a KBK hoist, and then positioned and assembled after the production line stops; Solution 3: A traveling mounting machine and telescopic forklifts are used, with the mounting machine following the main line while the vehicle is moving, and the forklifts extend synchronously to insert the battery pack directly under the chassis to complete the assembly. These solutions have the following drawbacks: (1) Offline static assembly requires the vehicle to be removed from the production line for separate processing. It is impossible to complete the assembly and related equipotential and insulation tests online, which increases the cost of manual towing and rework. (2) Online fixed-point hoisting and assembly: Because the battery pack is in the form of multiple parts, the overall assembly time is long. The production line needs to be stopped for a long time during fixed-point assembly, which seriously affects the overall production line JPH. (3) Although online dynamic assembly reduces downtime, the alignment of holes between the frame and the battery pack is difficult and time-consuming under dynamic conditions. Operators need to move with the vehicle to complete the assembly, making it difficult to guarantee the safety of the operation. Summary of the Invention

[0003] This application provides an online fixed-point assembly method and system for bottom-mounted battery packs of new energy trucks, which solves the technical problem that the existing technology's independent working systems cannot balance accuracy and efficiency, resulting in excessive downtime during assembly, affecting cycle time and poor assembly accuracy.

[0004] In a first aspect, embodiments of this application provide an online fixed-point assembly method for a new energy truck's under-mounted battery pack, comprising: The battery pack is transferred from the buffer area to the lineside transfer station next to the assembly line, where it is positioned and its attitude is adjusted in multiple degrees of freedom to be in the target position and attitude for assembly. The vehicle frame assembly is carried along the assembly line and stopped at the assembly station; the adjusted battery pack is then assembled into the vehicle frame assembly. After assembly, the transfer AGV is controlled to run at a speed higher than normal to catch up, so that the production line cycle time is restored to the preset cycle time.

[0005] In conjunction with the first aspect, in one embodiment, assembling the battery pack into the vehicle frame assembly (1) includes the following steps: Pick up the battery pack that has been adjusted and move it directly under the frame assembly; Acquire images of the mounting holes on the vehicle frame assembly and calculate the positional deviation between the battery pack and the mounting holes; Make fine adjustments based on positional deviations to align the battery pack mounting holes with the frame mounting holes. Lift the battery pack to the installation position so that the guide pin on the battery pack enters the mounting positioning hole on the frame assembly; complete the installation of the connecting bolts between the battery pack and the frame assembly.

[0006] In conjunction with the first aspect, in one implementation, after assembly, the transfer AGV is controlled to run at a catch-up speed higher than normal to restore the production line cycle time to the preset cycle time, which includes the following steps: Obtain the actual time consumed in the assembly operation; Calculate the time difference that needs to be caught up based on the preset cycle time of the production line and the actual time consumed; Calculate the catching-up speed based on the time difference and the remaining distance of the catching-up segment; control the dual-vehicle linkage AGV system to accelerate at the catching-up speed; when the actual progress of the dual-vehicle linkage AGV system is synchronized with the preset cycle time of the production line, control the dual-vehicle linkage AGV system to return to the normal driving speed.

[0007] Secondly, embodiments of this application provide an online fixed-point assembly system for under-mounted battery packs in new energy trucks, characterized in that it includes: The battery pack transfer and line-side buffer system is used to transfer the battery pack from the buffer area to the line-side transfer station next to the assembly line, and to position and adjust the battery pack with multiple degrees of freedom so that the battery pack is in the target position and attitude to be assembled. The dual-vehicle linkage AGV system is used to carry the chassis assembly and move it along the assembly line, stopping the trolley at the designated assembly station; The fixed-point assembly workstation is used to acquire the battery pack that has been adjusted in position and assemble the battery pack into the vehicle frame assembly; The cycle time catch-up control system is used to control the transfer AGV to run at a catch-up speed higher than the normal speed after assembly, so that the production line cycle time is restored to the preset cycle time.

[0008] In conjunction with the second aspect, in one embodiment, the battery pack transfer and line-side buffer system includes a transfer AGV, a line-side transfer station, and a battery pack attitude adjustment platform; the transfer AGV is used to transport a pallet loaded with battery packs from the battery pack buffer area to the line-side transfer station. The line-side transfer station is located next to the assembly station. It includes a positioning and lifting slide and a pallet detachment mechanism. The positioning and lifting slide is located on the working surface of the line-side transfer station for positioning the pallet. The pallet detachment mechanism is located adjacent to the positioning and lifting slide for separating the transfer AGV from the pallet after positioning is completed. The battery pack attitude adjustment platform is located between the lineside transfer station and the fixed-point assembly workstation to receive battery packs from the lineside transfer station and perform multi-degree-of-freedom attitude adjustment on the battery packs so that they are in the target position and target attitude to be assembled.

[0009] In conjunction with the second aspect, in one embodiment, the battery pack attitude adjustment platform includes an X-axis forward tray, a horizontal fine-tuning tray, a lifting tray, and a visual positioning system. The X-axis forward tray is used to adjust the position of the battery pack in the horizontal forward and backward direction; the lifting tray is used to lift the battery pack to the preset assembly height; the horizontal fine-tuning tray is used to adjust the position of the battery pack in the horizontal and vertical directions of the horizontal plane and rotates relative to the central axis of the lifting tray. The visual positioning system is connected to the X-axis forward tray, the horizontal fine-tuning tray, and the lifting tray via signals.

[0010] In conjunction with the second aspect, in one implementation, the dual-vehicle linkage AGV system includes a front AGV and a rear AGV; The front AGV is positioned below the front of the chassis assembly to support the front of the chassis assembly; the rear AGV is positioned below the rear of the chassis assembly to support the rear of the chassis assembly; the front AGV and the rear AGV are positioned close to or far apart from each other along the length of the chassis assembly to adapt to the chassis assembly.

[0011] In conjunction with the second aspect, in one embodiment, the fixed-point assembly workstation includes a telescopic fork mechanism (4) and a bolt fastening station; The telescopic fork mechanism is installed on the fixed assembly workstation to pick up the battery packs that have been adjusted in position from the battery pack transfer and line-side buffer system and move the battery packs to the underside of the chassis assembly; the telescopic fork mechanism can extend and retract horizontally, make minor adjustments left and right, and lift and lower vertically; The bolt fastening station is located next to the telescopic fork mechanism to complete the installation of the connecting bolts between the battery pack and the frame assembly.

[0012] In conjunction with the second aspect, in one embodiment, a vision guidance system is provided on the telescopic fork mechanism; The vision guidance system includes an industrial camera and a laser sensor, both of which are positioned facing the mounting holes of the chassis assembly.

[0013] In conjunction with the second aspect, in one implementation, the beat-catching control system includes a speed detection module, a beat calculation module, and an acceleration control module; The speed detection module is installed on the dual-vehicle linkage AGV system to detect the driving speed and current position of the dual-vehicle linkage AGV system in real time; The cycle time calculation module is connected to the speed detection module to calculate the time difference that needs to be caught up based on the actual time of the assembly operation and the preset cycle time of the production line. The acceleration control module is connected to the cycle time calculation module to calculate the catch-up speed based on the time difference and the remaining distance of the catch-up segment, and control the dual-vehicle linkage AGV system to run at the catch-up speed until it is synchronized with the preset cycle time of the production line and then returns to the normal driving speed.

[0014] The beneficial effects of the technical solutions provided in this application include: A method for online fixed-point assembly of under-mounted battery packs for new energy trucks is proposed. The battery packs are pre-transferred from the buffer area to a line-side transfer station next to the assembly line, where they are positioned and adjusted for multiple degrees of freedom before assembly. This ensures the battery packs are in the target position and posture for assembly while waiting at the assembly station, avoiding waiting time caused by delayed arrival. The vehicle frame assembly travels along the assembly line, stopping the trolley at the assembly station. Under static conditions, the adjusted battery packs are assembled onto the frame assembly. This fixed-point stopping ensures that operators can complete hole alignment and bolt installation while stationary, eliminating the alignment difficulties and operational safety issues associated with dynamic following assembly, and ensuring assembly accuracy. Finally, after assembly, the transfer AGV is controlled to run at a higher-than-normal speed to compensate for the downtime caused by the fixed-point stopping through speed compensation in subsequent sections, restoring the cycle time of the entire production line to the preset value. By pre-processing to ensure readiness, fixed-point stopping to ensure accuracy, and accelerating the recovery of the production cycle, the traditionally conflicting concepts of accuracy and efficiency are unified into a whole. This not only ensures high accuracy in static assembly but also maintains the preset production cycle through speed compensation. It solves the technical problem that existing technologies, where each working system is independent and cannot balance accuracy and efficiency, lead to excessive downtime during assembly, affecting the production cycle and resulting in poor assembly accuracy. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of the online fixed-point assembly system for the under-mounted battery pack of a new energy truck provided in an embodiment of this application; Figure 2 A schematic diagram illustrating the entire process of assembling the bottom-mounted battery, provided for an embodiment of this application; Figure 3 This is a schematic diagram of the fixed-point assembly method provided in the embodiments of this application; Figure 4 This is a schematic diagram of the control logic for the empty / full switching of the transfer AGV provided in the embodiments of this application; Figure 5 This is a schematic diagram of the beat-catching control logic provided in the embodiments of this application; Figure 6 This is a schematic diagram of the relevant structure of the transfer vehicle frame assembly provided in the embodiments of this application; Figure 7 This is a schematic diagram of the motion of the telescopic fork mechanism provided in the embodiments of this application; Figure 8 This is a schematic diagram of the tray empty / full exchange area provided in an embodiment of this application.

[0017] In the diagram: 1. Chassis assembly; 2. Front AGV; 3. Rear AGV; 4. Telescopic fork mechanism. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0019] To make the technical problem that this application aims to solve clearer, the causes of the technical problem will be analyzed in detail below: In existing technologies, the assembly of bottom-mounted battery packs mainly follows two independent technical routes: the stop-assemble-move mode, which requires the production line to stop for extended periods at the assembly station to ensure assembly accuracy, until the battery pack is manually positioned, aligned, and bolted. The fundamental flaw of this mode is that it completely incorporates the assembly operation time into the production line cycle time, leading to a significant decrease in the production line's JPH (Joint Power Per Hour). Especially for bottom-mounted battery packs, due to the limited space under the vehicle frame and difficulties in aligning holes, each assembly operation takes a long time, with downtime far exceeding the production line's allowable buffer range. The following mode, the follow-assemble-move mode, requires operators to dynamically align and install the battery pack while the vehicle is moving to maintain continuous production line operation. The fundamental flaw of this mode is that the relative position between the vehicle frame and the battery pack constantly changes under dynamic conditions, making hole alignment extremely difficult. Operators must move with the vehicle, which not only demands extremely high skill levels but also poses serious safety hazards, resulting in lower actual assembly efficiency and yield rates than expected.

[0020] In existing technologies, battery packs are typically transported directly from the buffer area to the assembly station by forklifts, overhead cranes, or AGVs, directly participating in the assembly process. The drawbacks of this approach are: positioning errors generated during transportation cannot be effectively eliminated before assembly; all alignment work must be completed in one go at the assembly station, increasing the difficulty and time consumption of assembly. Logistics AGVs must wait in place during assembly and cannot be deployed for the next trip, resulting in low AGV utilization and limited overall system logistics efficiency. The lack of a line-side buffer mechanism prevents the pre-positioning and attitude pre-adjustment of battery packs; the assembly station must wait for the battery packs to arrive before starting operations, creating a sequential waiting bottleneck.

[0021] On production lines where gasoline and electric vehicles operate in parallel, electric vehicles require under-mounted battery pack assembly, while gasoline vehicles do not. In existing technologies, the assembly station often performs a line stop operation for all vehicle models equally, or requires manual judgment to determine whether assembly should proceed. This results in the production line being forced to stop or slow down when a gasoline vehicle passes the assembly station, causing unnecessary cycle time waste. The lack of an automatic identification mechanism linked to the MES system prevents the intelligent skipping of the assembly process based on vehicle model information, impacting the flexibility of mixed-flow production.

[0022] In existing fixed-point assembly schemes, downtime caused by assembly is considered a fixed loss, with no mechanism to compensate for it. However, in actual production, assembly time is highly variable, influenced by factors such as operator skill, battery pack model, and hole position deviations. The lack of a speed compensation algorithm means that the production line cycle time can only be designed based on the maximum possible downtime, resulting in a lower designed production capacity. Once assembly timeouts occur, the accumulated delay is propagated, affecting the operational rhythm of all subsequent workstations.

[0023] Firstly, referring to Figures 1 to 8This application proposes an online fixed-point assembly method for under-floor battery packs in new energy trucks, which includes: S100: Transfer the battery pack from the buffer area to the lineside transfer station next to the assembly line, and perform positioning and multi-degree-of-freedom attitude adjustment on the battery pack so that the battery pack is in the target position and attitude to be assembled. S200, carrying the frame assembly 1 and moving it along the assembly line, stopping the trolley at the assembly station; assembling the adjusted battery pack to be assembled into the frame assembly 1; After the S300 assembly is completed, the control transfer AGV runs at a speed higher than normal to catch up, so that the production line cycle time is restored to the preset cycle time.

[0024] This method involves pre-transferring the battery pack from the buffer area to a line-side transfer station next to the assembly line, and completing its positioning and multi-degree-of-freedom attitude adjustment before assembly. This ensures that the battery pack is already in the target position and attitude for assembly while waiting at the assembly station, avoiding waiting time caused by delayed arrival of the battery pack. The carrying frame assembly travels along the assembly line, stopping the trolley at a fixed point at the assembly station. Under static conditions, the battery pack, with its attitude already adjusted, is assembled into the frame assembly. This fixed-point stopping ensures that the operator can complete hole alignment and bolt installation while stationary, eliminating the problems of high alignment difficulty and low operational safety caused by dynamic following assembly, and ensuring assembly accuracy. Finally, after assembly, the transfer AGV is controlled to run at a speed higher than normal to catch up, and the downtime caused by the fixed-point stopping is compensated by the speed of subsequent sections, restoring the cycle time of the entire production line to the preset value. By pre-processing to ensure readiness, fixed-point stopping to ensure accuracy, and accelerating the recovery of the production cycle, the traditionally conflicting concepts of accuracy and efficiency are unified into a whole. This not only ensures high accuracy in static assembly but also maintains the preset production cycle through speed compensation. It solves the technical problem that existing technologies, where each working system is independent and cannot balance accuracy and efficiency, lead to excessive downtime during assembly, affecting the production cycle and resulting in poor assembly accuracy.

[0025] Furthermore, in one embodiment, assembling the battery pack into the vehicle frame assembly 1 includes the following steps: Pick up the battery pack that has been adjusted and move it to the bottom of the frame assembly 1; Acquire images of the mounting holes on the frame assembly 1 and calculate the positional deviation between the battery pack and the mounting holes; Make fine adjustments based on positional deviations to align the battery pack mounting holes with the frame mounting holes. Lift the battery pack to the installation position so that the guide pin on the battery pack enters the mounting positioning hole on the frame assembly 1; complete the installation of the connecting bolts between the battery pack and the frame assembly 1.

[0026] In this embodiment, by forking the battery pack with its adjusted posture and moving it directly under the vehicle frame, the battery pack is precisely transferred from the line-side buffer to the assembly position, laying the foundation for subsequent alignment. Secondly, by acquiring images of the mounting holes on the vehicle frame and calculating the positional deviation, a visually guided closed-loop control mechanism is introduced, transforming the traditional hole alignment process, which relies on manual experience and visual observation, into a data-driven automated alignment, improving alignment accuracy and consistency. Thirdly, fine-tuning is performed based on the deviation value to ensure precise alignment between the battery pack mounting holes and the vehicle frame holes, effectively compensating for the positioning errors accumulated in previous steps and ensuring assembly accuracy. Then, a mechanical guidance method using guide pins to enter the mounting positioning holes provides reliable physical guidance during the final insertion stage, further ensuring the accuracy and reliability of the assembly. Finally, bolt installation is completed under static conditions, eliminating the need for operators to follow the moving vehicle, reducing operational difficulty and labor intensity while improving operational safety.

[0027] Furthermore, in one embodiment, after assembly, the transfer AGV is controlled to run at a catch-up speed higher than the normal speed to restore the production line cycle time to the preset cycle time, which includes the following steps: Obtain the actual time consumed in the assembly operation; Calculate the time difference that needs to be caught up based on the preset cycle time of the production line and the actual time consumed; Calculate the catching-up speed based on the time difference and the remaining distance of the catching-up segment; control the dual-vehicle linkage AGV system to accelerate at the catching-up speed; when the actual progress of the dual-vehicle linkage AGV system is synchronized with the preset rhythm of the production line, control the dual-vehicle linkage AGV system to return to the normal driving speed.

[0028] In this embodiment, by acquiring the actual time consumed in the assembly operation, the time consumption of the assembly process is accurately quantified, providing an accurate data foundation for subsequent speed compensation. Secondly, the time difference to be caught up is calculated based on the difference between the preset cycle time and the actual time consumed, transforming cycle time recovery into a specific and quantifiable time compensation amount, making the control objective clear and explicit. Thirdly, the catching-up speed is dynamically calculated based on the time difference and the remaining distance of the catching-up segment, rather than using a fixed acceleration or speed value, ensuring the adaptability and accuracy of the catching-up strategy. When the remaining distance is short, the catching-up speed is automatically increased; when the remaining distance is sufficient, the catching-up speed can be appropriately reduced, avoiding cycle time disorder caused by over-catching or under-catching. Then, by controlling the dual-vehicle linkage AGV system to accelerate at the calculated catching-up speed, accurate compensation for downtime is achieved. Finally, when the actual progress is synchronized with the preset cycle time, the normal driving speed is restored, forming a complete closed-loop control loop, ensuring that the production line can accurately recover to the original cycle time after experiencing assembly stoppage, without accumulating delays.

[0029] The specific assembly process is as follows: Battery pack transfer and line-side buffering: The MES system issues battery pack demand instructions based on the production plan. The battery pack transfer AGV picks up the corresponding model of battery pack (with a pallet) from the battery pack buffer area and travels to the line-side transfer station next to the assembly line. At the line-side transfer station, a positioning lifting slide rises and precisely positions the pallet on the slide by engaging with the positioning holes on the bottom of the pallet using positioning pins. After positioning, the pallet detachment mechanism automatically separates the transfer AGV from the pallet, and the transfer AGV either drives away empty or returns to the buffer area with an empty pallet for the next transport task.

[0030] Battery pack retrieval and attitude adjustment: A gantry-type gantry robot or a dedicated forklift mechanism retrieves the battery pack from the positioning and lifting slide at the line-side transfer station and transfers it to the battery pack attitude adjustment platform in the assembly preparation area. Based on the current vehicle model information issued by the MES (Manufacturing Execution System), the attitude adjustment platform performs multi-degree-of-freedom attitude fine-tuning of the battery pack in the X, Y, Z directions, and rotation angles through the coordinated operation of the X-axis forward pallet, horizontal fine-tuning pallet, and lifting pallet, positioning the battery pack in the target position and attitude for assembly. Simultaneously, a vision positioning system collects positioning feature information from the battery pack, providing reference data for subsequent assembly.

[0031] Vehicle type recognition and mainline AGV positioning: The dual-vehicle linkage mainline AGV system carries the light truck frame assembly 1 along the assembly line. When the vehicle arrives at the preset trigger position before the assembly station, the AGV scheduling system automatically determines the vehicle type based on the vehicle type information issued by the MES: if it is an electric vehicle (requiring an under-mounted battery pack), a stop command is issued, and the front AGV2 and the rear AGV3 simultaneously decelerate to a fixed stop, with the frame assembly 1 precisely positioned above the assembly work area; if it is a gasoline vehicle (no battery pack required), the AGV system passes directly through the assembly station, and the assembly workstation is in standby mode.

[0032] Telescopic fork pickup and secondary attitude fine-tuning: The telescopic fork mechanism 4 picks up the battery pack with its adjusted attitude from the battery pack attitude adjustment platform and moves it directly below the frame assembly 1. The lifting mechanism of the telescopic forks raises the battery pack to near the installation position. The industrial camera and laser sensor in the vision guidance system capture images of the mounting hole positions on the frame, and the control system calculates the positional deviation between the battery pack mounting holes and the frame holes. The fine-tuning mechanism of the telescopic forks performs precise fine-tuning in the X, Y, and Z directions based on the deviation value, ensuring accurate alignment between the battery pack mounting holes and the frame holes. Subsequently, the lifting mechanism continues to rise, causing the guide pin on the battery pack to enter the mounting positioning hole on the frame, completing the guided insertion.

[0033] Manual fine-tuning and bolt installation: The operator observes the fit between the guide pin and the positioning hole, and performs manual fine-tuning using the fine-tuning control handle of the telescopic fork to ensure that the positioning pin is fully engaged in the positioning hole. After confirming that the position is correct, the operator uses an electric tightening tool to install the connecting bolts between the battery pack and the frame assembly 1, completing the fixed connection between the battery pack and the frame.

[0034] The telescopic fork descent and reset, along with the main line AGV's acceleration to catch up: After assembly, the telescopic fork descends to its initial height, and the fork arms retract from the bottom of the battery pack and return to their original position. Once the telescopic fork is back in position, it sends an "Assembly Complete" signal to the assembly workstation PLC, which forwards this signal to the AGV scheduling system. The AGV scheduling system obtains the actual assembly time, calculates the time difference needed to catch up based on the production line's preset cycle time, and dynamically calculates the catching-up speed based on the remaining distance in the catching-up section. The preceding AGV2 accelerates at this catching-up speed, while the following AGV3 maintains the same speed, gradually synchronizing the actual progress of the dual-vehicle linked AGV system with the production line's preset cycle time. Once synchronization is complete, the AGVs return to their normal operating speed.

[0035] Moving to the next assembly station: The main line AGV continues to move at normal speed, passing through the subsequent assembly stations in sequence until the complete vehicle assembly is completed and it rolls off the line.

[0036] Secondly, this application proposes an online fixed-point assembly system for under-mounted battery packs in new energy trucks, which includes: The battery pack transfer and line-side buffer system is used to transfer the battery pack from the buffer area to the line-side transfer station next to the assembly line, and to position and adjust the battery pack with multiple degrees of freedom so that the battery pack is in the target position and attitude to be assembled. The dual-vehicle linkage AGV system is used to carry the chassis assembly 1 and move it along the assembly line, stopping the trolley at the assembly station. The fixed-point assembly workstation is used to acquire the battery pack that has been adjusted in attitude and assemble the battery pack into the frame assembly 1; The cycle time catch-up control system is used to control the transfer AGV to run at a catch-up speed higher than the normal speed after assembly, so that the production line cycle time is restored to the preset cycle time.

[0037] By setting up this system, the battery pack transfer and line-side buffer system pre-transfers the battery packs to a line-side transfer station next to the assembly line for positioning and attitude adjustment, avoiding the waiting and interference caused by the battery packs directly participating in the main line transportation. Subsequently, the dual-vehicle linkage AGV system carries the chassis assembly 1 along the assembly line and judges the vehicle type based on the vehicle information. If it is an electric vehicle, it stops at a fixed point at the assembly station; if it is a gasoline vehicle, it passes directly, realizing accurate scheduling of mixed electric and gasoline vehicles. Next, the fixed-point assembly station obtains the battery pack with the adjusted attitude and completes the assembly of the battery pack and the chassis under the static condition of the AGV system stopping at a fixed point. This eliminates the problems of high alignment difficulty and unsafe operation caused by dynamic following assembly and ensures assembly accuracy. Finally, the cycle time chasing control system controls the dual-vehicle linkage AGV system to run at a chasing speed higher than the normal speed after the assembly is completed. The time lost due to the fixed-point stop is compensated by the speed of the subsequent section, so that the cycle time of the entire production line is restored to the preset value. This system ensures accuracy and safety through fixed-point assembly and accelerates the recovery of the production cycle. It solves the technical problem that existing technologies, where each working system is independent and cannot balance accuracy and efficiency, result in excessive downtime during assembly, affecting the production cycle and causing poor assembly accuracy.

[0038] Furthermore, in one embodiment, the battery pack transfer and line-side buffer system includes a transfer AGV, a line-side transfer station, and a battery pack attitude adjustment platform; the transfer AGV is used to transport a tray loaded with battery packs from the battery pack buffer area to the line-side transfer station; The line-side transfer station is located next to the assembly station. It includes a positioning and lifting slide and a pallet detachment mechanism. The positioning and lifting slide is located on the working surface of the line-side transfer station for positioning the pallet. The pallet detachment mechanism is located adjacent to the positioning and lifting slide for separating the transfer AGV from the pallet after positioning is completed. The battery pack attitude adjustment platform is located between the lineside transfer station and the fixed-point assembly workstation to receive battery packs from the lineside transfer station and perform multi-degree-of-freedom attitude adjustment on the battery packs so that they are in the target position and target attitude to be assembled.

[0039] In this embodiment, the transfer AGV transports a pallet loaded with battery packs from the buffer area to the line-side transfer station next to the assembly station. The positioning and lifting slide in the line-side transfer station precisely positions the pallet. After positioning, the pallet detachment mechanism automatically separates the transfer AGV from the pallet, allowing the transfer AGV to immediately depart empty for the next transport task without waiting at the assembly station, thus improving AGV turnover and overall system logistics efficiency. Simultaneously, the battery pack attitude adjustment platform performs multi-degree-of-freedom attitude adjustment on the battery packs, ensuring they are in the target position and attitude before assembly. This pre-processing and precise positioning of the battery pack attitude saves on-site adjustment time for subsequent assembly operations and allows the logistics and assembly processes to operate in parallel, avoiding the serial waiting bottleneck caused by the direct involvement of battery packs in assembly in traditional solutions. Furthermore, in one embodiment, the battery pack attitude adjustment platform includes an X-axis forward tray, a horizontal fine-tuning tray, a lifting tray, and a visual positioning system; The X-axis forward tray is used to adjust the position of the battery pack in the horizontal forward and backward direction; the lifting tray is used to lift the battery pack to the preset assembly height; the horizontal fine-tuning tray is used to adjust the position of the battery pack in the horizontal and vertical directions of the horizontal plane and rotates relative to the central axis of the lifting tray. The visual positioning system is connected to the X-axis forward tray, the horizontal fine-tuning tray, and the lifting tray via signals.

[0040] In this embodiment, the X-axis forward tray is used to adjust the position of the battery pack along the horizontal front-to-back direction, the horizontal fine-tuning tray is used to adjust the position of the battery pack along the horizontal and vertical directions of the horizontal plane and rotate relative to the central axis of the lifting tray, and the lifting tray is used to lift the battery pack to the preset assembly height. The vision positioning system collects the positioning feature information of the battery pack, connects with the signals of each tray, and controls their coordinated actions, thereby realizing all-round precise fine-tuning of the battery pack in the X, Y, Z directions and rotation angles. Through the multi-level linkage adjustment mechanism, the battery pack can be accurately adjusted to the target position and target posture before assembly, eliminating the positioning error accumulated by the battery pack during transportation and transfer. This allows subsequent assembly operations to complete the alignment with only minor secondary fine-tuning, shortening the on-site adjustment time at the assembly station and improving the assembly success rate and work efficiency. At the same time, the introduction of the vision positioning system realizes the automation and closed-loop control of posture adjustment, reducing the skill requirements and labor intensity of manual operation.

[0041] It should be noted that, in this embodiment, the X-axis forward tray can be displaced 0mm-20mm forward and backward in the horizontal direction; the horizontal fine-tuning tray can be limited to displacement ±50mm in the X and Y directions of the horizontal plane, and can rotate ±4° relative to the X-axis centerline of the lifting tray; the lifting tray is used to lift the battery pack to the preset assembly height, and the Z-axis lifting positioning accuracy can reach ±0.5mm.

[0042] Furthermore, in one embodiment, the dual-vehicle linkage AGV system includes a front AGV2 and a rear AGV3; The front AGV2 is located below the front of the frame assembly 1 to support the front of the frame assembly 1, and the rear AGV3 is located below the rear of the frame assembly 1 to support the rear of the frame assembly 1. The front AGV2 and the rear AGV3 are close to or far apart from each other along the length of the frame assembly 1 to adapt to the frame assembly 1.

[0043] In this embodiment, the front AGV2 supports the front part of the chassis assembly 1 (front axle crossbeam), and the rear AGV3 supports the rear part of the chassis assembly 1 (middle and rear axles). Both AGVs, through an adjustable support device, can automatically adjust their support positions according to the vehicle wheelbase information issued by the MES, thus adapting to light truck models with different wheelbases. On one hand, the dual-vehicle linkage AGV system replaces the traditional fixed plate chain conveyor line, reducing ground infrastructure construction and equipment investment costs, while improving the flexibility and fault tolerance of the production line operation. On the other hand, the introduction of the adjustable support device allows the same AGV system to support chassis assemblies 1 with multiple wheelbases without changing tooling or manual adjustment, enabling mixed-line production of multiple vehicle models such as gasoline and electric vehicles, and enhancing the changeover efficiency of the production line. Furthermore, when the rear AGV3 is under load, its walking power is cut off, retaining only its steering function, with traction power provided by the front AGV2. The AGV scheduling system interacts with the MES system in real time to obtain the current wheelbase and vehicle model information of the chassis assembly 1, realizing automatic adjustment of the distance between the front and rear AGVs.

[0044] Furthermore, in one embodiment, the fixed-point assembly workstation includes a telescopic fork mechanism 4 and a bolt fastening station; The telescopic fork mechanism 4 is installed on the fixed assembly workstation to pick up the battery pack with the adjusted posture from the battery pack transfer and line-side buffer system and move the battery pack to the underside of the frame assembly 1; the telescopic fork mechanism 4 can extend and retract horizontally, make slight adjustments left and right, and lift and lower vertically. The bolt fastening station is located next to the telescopic fork mechanism 4 to complete the installation of the connecting bolts between the battery pack and the frame assembly 1.

[0045] In this embodiment, the telescopic fork mechanism 4 replaces the traditional lifting KBK hoist or manual forklift operation. Through its three-degree-of-freedom motion capability, it achieves precise transfer and fine-tuning of the battery pack, ensuring accurate alignment between the battery pack mounting holes and the frame holes. At the same time, the assembly process adopts a fixed-point assembly mode, eliminating the need for operators to follow the moving vehicle to complete the assembly operation. Operators can comfortably complete hole alignment and bolt installation at fixed bolt tightening positions, reducing the difficulty and labor intensity of manual operation, improving operational safety, and ensuring a unified guarantee of the accuracy, efficiency, and safety of the assembly operation.

[0046] Furthermore, in one embodiment, the telescopic fork mechanism 4 is equipped with a visual guidance system; The vision guidance system includes an industrial camera and a laser sensor, both of which are positioned toward the mounting holes of the frame assembly 1 to acquire images of the mounting holes on the frame assembly 1 and calculate the positional deviation between the battery pack and the mounting holes based on the images, so that the mounting holes of the battery pack are aligned with the mounting holes of the frame.

[0047] In this embodiment, the introduction of a vision guidance system enables closed-loop automatic control of the assembly process. Industrial cameras and laser sensors can acquire the position information of the mounting holes on the chassis in real time and with precision. The control system calculates the deviation based on this information and drives the telescopic fork mechanism 4 to perform precise fine-tuning, thereby improving the alignment accuracy between the battery pack and the chassis holes and compensating for AGV positioning deviation, chassis manufacturing tolerance, and residual errors from previous posture adjustments. At the same time, this solution transforms the traditional hole alignment process, which relies on operator visual observation and experience judgment, into an automated and visualized precise operation, reducing the skill requirements for operators, shortening the hole alignment time, and improving the assembly success rate and operational efficiency.

[0048] Furthermore, in one embodiment, the beat-catching control system includes a speed detection module, a beat calculation module, and an acceleration control module; The speed detection module is installed on the dual-vehicle linkage AGV system to detect the system's speed and current position in real time. The cycle time calculation module is connected to the speed detection module to calculate the time difference that needs to be caught up based on the actual time taken for the assembly operation and the preset cycle time of the production line. The acceleration control module is connected to the cycle time calculation module to calculate the catching-up speed after the assembly is completed, based on the time difference and the remaining distance of the catching-up section, and control the dual-vehicle linkage AGV system to run at the catching-up speed until it is synchronized with the preset cycle time of the production line and then returns to the normal driving speed.

[0049] In this embodiment, by converting the downtime caused by battery pack assembly into acceleration compensation for subsequent sections, the accuracy of fixed-point stops and the uniformity of accelerated catch-up recovery are achieved. This ensures that the cycle time of the entire production line is not affected by the battery pack assembly process, and the JPH of the production line remains stable. At the same time, the catch-up speed is dynamically calculated based on the remaining distance and remaining time, rather than using a fixed acceleration or fixed speed, which ensures the accuracy of cycle time recovery and avoids cycle time disorder caused by over-catching up or under-catching up. This provides precise speed control assurance for high-cycle, high-efficiency mixed-flow production.

[0050] It is important to know that, as a reference Figure 8In a preferred embodiment of the present invention, to further improve the utilization efficiency of the battery pack transfer AGV and reduce empty runs, the line-side transfer station adopts a dual-station series buffer mechanism, and is equipped with a forward-pushing and switching engagement empty-full exchange mode, specifically: Traditional AGVs, after transporting battery packs, typically need to exit the lineside transfer station empty and then travel to the empty equipment storage station for attachment. This process generates an additional empty trip, resulting in low AGV turnover efficiency and extended single transport cycles. To address this issue, this embodiment sets up two stations arranged in series along the AGV's travel direction at the lineside transfer station: the upstream station is used to locate and store empty equipment (empty tools loaded onto the vehicle or empty pallets), and the downstream station is used to release and temporarily store fully loaded equipment carrying battery packs. Empty equipment can be released by the previous AGV and remain there directly, or it can be transported to the upstream station for pre-positioning via the empty pallet return line.

[0051] An AGV carrying a full load of equipment enters the lineside transfer station from downstream. At this point, an empty load has already occupied the upstream workstation. The AGV first enters under the empty load (or docks with its rear) using a stealthy lifting or stealthy traction method, then pushes its full load to the downstream workstation through continuous forward movement, releasing the full load. During this process, the AGV automatically engages with the empty load, then carries the empty load back to the lineside transfer station and returns to the buffer area for the next round of transport.

[0052] To ensure the safety and positioning accuracy of the AGV when drilling under empty containers and pushing full containers, the docking and buffering mechanism is equipped with ground positioning pins, limit blocks, and photoelectric sensors. The ground positioning pins mechanically guide the AGV's path, the limit blocks restrict the extreme positions of the AGV and containers, and the photoelectric sensors detect the relative positions of the AGV, full containers, and empty containers in real time. These three components work together to ensure that the AGV does not collide or deviate when completing the unloading and emptying operations in confined spaces. Through this design, the AGV can complete the release of full containers and the attachment of empty containers in a single stop, eliminating the need for additional empty detours. This shortens the single transport cycle, improves the AGV's turnover efficiency, reduces the system's requirement for a larger number of AGVs, and thus saves on equipment investment costs and operating energy consumption.

[0053] like Figure 5 As shown, V is the current travel speed of the AGV, V0 is the set standard operating speed of the AGV on the assembly line, and V max This represents the maximum operating speed of the AGV.

[0054] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0055] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0056] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for online fixed-point assembly of a bottom-mounted battery pack for a new energy truck, characterized in that, It includes: The battery pack is transferred from the buffer area to the lineside transfer station next to the assembly line, where it is positioned and its attitude is adjusted in multiple degrees of freedom to be in the target position and attitude for assembly. Carry the frame assembly (1) and move it along the assembly line, stop the electric vehicle at the assembly station; assemble the adjusted battery pack to the frame assembly (1). After assembly, the transfer AGV is controlled to run at a speed higher than normal to catch up, so that the production line cycle time is restored to the preset cycle time.

2. The online fixed-point assembly method for the under-mounted battery pack of a new energy truck as described in claim 1, characterized in that, The battery pack is assembled into the vehicle frame assembly (1), which includes the following steps: Pick up the battery pack that has been adjusted and move it to the bottom of the frame assembly (1); Images of mounting holes on the vehicle frame assembly (1) are collected, and the positional deviation between the battery pack and the mounting holes is calculated. Fine-tune according to the positional deviation to align the mounting holes of the battery pack with the mounting holes of the vehicle frame; Lift the battery pack to the installation position so that the guide pin on the battery pack enters the mounting positioning hole on the frame assembly (1); complete the installation of the connecting bolts between the battery pack and the frame assembly (1).

3. The online fixed-point assembly method for the under-mounted battery pack of new energy trucks as described in claim 1, characterized in that, After assembly, the transfer AGV is controlled to run at a speed higher than normal to catch up, so that the production line cycle time returns to the preset cycle time. This includes the following steps: Obtain the actual time consumed in the assembly operation; Calculate the time difference that needs to be caught up based on the preset cycle time of the production line and the actual time consumed; Based on the time difference and the remaining distance of the catch-up segment, the catch-up speed is calculated; the dual-vehicle linkage AGV system is controlled to accelerate at the catch-up speed; when the actual progress of the dual-vehicle linkage AGV system is synchronized with the preset rhythm of the production line, the dual-vehicle linkage AGV system is controlled to return to the normal driving speed.

4. A system for online fixed-point assembly of under-mounted battery packs for new energy trucks, characterized in that, It includes: The battery pack transfer and line-side buffer system is used to transfer the battery pack from the buffer area to the line-side transfer station next to the assembly line, and to position and adjust the battery pack with multiple degrees of freedom so that the battery pack is in the target position and attitude to be assembled. The dual-vehicle linkage AGV system is used to carry the chassis assembly (1) and move it along the assembly line, stopping the trolley at the assembly station; A fixed-point assembly workstation is used to acquire the battery pack with the adjusted posture and assemble the battery pack into the vehicle frame assembly (1). The cycle time catch-up control system is used to control the transfer AGV to run at a catch-up speed higher than the normal speed after assembly, so that the production line cycle time is restored to the preset cycle time.

5. The online fixed-point assembly system for under-mounted battery packs of new energy trucks as described in claim 4, characterized in that: The battery pack transfer and line-side buffer system includes a transfer AGV, a line-side transfer station, and a battery pack attitude adjustment platform; the transfer AGV is used to transport a pallet loaded with battery packs from the battery pack buffer area to the line-side transfer station; The line-side transfer station is located next to the assembly station and includes a positioning and lifting slide and a pallet detachment mechanism. The positioning and lifting slide is located on the working surface of the line-side transfer station for positioning the pallet. The pallet detachment mechanism is located adjacent to the positioning and lifting slide for separating the transfer AGV from the pallet after positioning is completed. The battery pack attitude adjustment platform is located between the line-side transfer station and the fixed-point assembly workstation to receive the battery pack from the line-side transfer station and perform multi-degree-of-freedom attitude adjustment on the battery pack so that it is in the target position and target attitude to be assembled.

6. The online fixed-point assembly system for under-mounted battery packs of new energy trucks as described in claim 5, characterized in that: The battery pack attitude adjustment platform includes an X-axis forward tray, a horizontal fine-tuning tray, a lifting tray, and a visual positioning system; The X-axis forward tray is used to adjust the position of the battery pack in the horizontal forward and backward direction; the lifting tray is used to lift the battery pack to a preset assembly height; the horizontal fine-tuning tray is used to adjust the position of the battery pack in the horizontal and vertical directions of the horizontal plane, and rotates relative to the central axis of the lifting tray. The visual positioning system is signal-connected to the X-axis forward tray, the horizontal fine-tuning tray, and the lifting tray.

7. The online fixed-point assembly system for under-mounted battery packs of new energy trucks as described in claim 4, characterized in that: The dual-vehicle linkage AGV system includes a front AGV (2) and a rear AGV (3). The front AGV (2) is located below the front of the frame assembly (1) to support the front of the frame assembly (1); the rear AGV (3) is located below the rear of the frame assembly (1) to support the rear of the frame assembly (1); the front AGV (2) and the rear AGV (3) move closer to or further away from each other along the length of the frame assembly (1) to adapt to the frame assembly (1).

8. The online fixed-point assembly system for under-mounted battery packs of new energy trucks as described in claim 4, characterized in that: The fixed-point assembly workstation includes a telescopic fork mechanism (4) and a bolt fastening station; The telescopic fork mechanism (4) is installed on the fixed-point assembly workstation to pick up the battery pack with the adjusted posture from the battery pack transfer and line-side buffer system and move the battery pack to the underside of the frame assembly (1); the telescopic fork mechanism (4) extends horizontally, makes slight adjustments left and right and lifts vertically; The bolt fastening station is located on the side of the telescopic fork mechanism (4) to complete the installation of the connecting bolts between the battery pack and the frame assembly (1).

9. The online fixed-point assembly system for undermount battery packs of new energy trucks as described in claim 8, characterized in that: The telescopic fork mechanism (4) is equipped with a vision guidance system; The vision guidance system includes an industrial camera and a laser sensor, both of which are positioned toward the mounting holes of the frame assembly (1).

10. The online fixed-point assembly system for undermount battery packs of new energy trucks as described in claim 4, characterized in that: The beat-chasing control system includes a speed detection module, a beat calculation module, and an acceleration control module; The speed detection module is installed on the dual-vehicle linkage AGV system to detect the driving speed and current position of the dual-vehicle linkage AGV system in real time. The cycle time calculation module is signal-connected to the speed detection module to calculate the time difference that needs to be caught up based on the actual time consumed by the assembly operation and the preset cycle time of the production line. The acceleration control module is signal-connected to the cycle calculation module to calculate the catch-up speed based on the time difference and the remaining distance of the catch-up segment, and to control the dual-vehicle linkage AGV system to run at the catch-up speed until it is synchronized with the preset cycle of the production line and then returns to the normal driving speed.

Images