1900 results about "Low speed" patented technology

Disclosed is a low-precision incremental encoder-based method for ultra-low speed control of a servo system. According to the present invention, a fast speed observer in an ultra-low-speed working state is achieved, only a sampling speed and load torque in an M / T method need to be observed, and position information of an electric motor does not need to be observed, such that the structure of the observer is simplified, and calculation is simple and fast; moreover, the influence of a friction force and cogging torque on a speed change is considered, such that the speed observation precision is further improved. The fast speed observer can reduce hysteresis and measurement dead zones, such that the speed response and the speed control precision in a low-speed working state are greatly improved, the problem in a traditional observer of a large position deviation caused by nonlinear factors such as an external load is avoided, improving the stability and robustness of the system. According to the present invention, the processing of sampling measurement time at a medium-high speed and the processing of switching the observer at a low speed in the M / T method can optimize the speed measurement precision at both the medium-high speed and the ultra-low speed, and can better satisfy the requirements of apparatuses such as a radar on rotating speed control.

The invention provides a multi-path main road signal cooperative control method considering speed fluctuation, and the method comprises the steps: firstly collecting traffic data, including road network geometric data, traffic flow data and signal control data, and determining a plurality of main paths according to the traffic flow data; then, based on the running speed of each vehicle on each main path, the vehicle running average speed and the speed fluctuation quantity on each main path are calculated; and finally, constructing a signal control optimization model: constructing a target function by taking weighted green wave bandwidth maximization of all paths as a target, adding a loop integer constraint, an interference constraint, a speed fluctuation space-time constraint, a highest speed fluctuation constraint and a lowest speed fluctuation constraint, solving the signal control optimization model, and obtaining an optimized signal period and green wave bandwidth. And outputting the optimized signal timing strategy. The signal timing generated by the method has a good prospect in the aspect of reducing travel delay and parking times, and a better multi-path collaborative effect can be realized.

Disclosed in the present application is a wheel anti-lock braking system applicable to hill braking. In the wheel anti-lock braking system, a wheel speed identification module is used for identifying a vehicle wheel speed signal and a wheel acceleration signal; a vehicle speed acquisition module is used for calculating a vehicle body speed signal; a driving intention identification module is used for obtaining a front and a rear axle enable flag bit; a state machine module is used for determining whether the working state of a low-speed hill anti-lock braking system is a standby state or a shutdown state, and starting a conventional anti-lock braking system when the working state of the low-speed hill anti-lock braking system is a shutdown state; the state machine module receives the front and rear axle enable flag bits, and transmits the front and rear axle enable flag bits to a control logic module when the working state of the low-speed hill anti-lock braking system is a standby state; and the control logic module is used for sending a low-speed hill anti-lock braking system control command when wheels show a tendency to lock up. The present application realizes anti-lock braking control over wheels at low speeds, especially during hill braking, which cannot be achieved by conventional wheel anti-lock braking systems.

The invention relates to the technical field of motor control, in particular to a speed sensorless control method of a long-stator linear motor for a maglev train in a full-speed domain range. According to the method, when the train runs at a low speed, the mechanical position sensor is adopted for control, and control precision is high; when the train runs at a high speed, speed sensorless control based on extended back electromotive force is adopted, so that control errors caused by data transmission delay can be avoided; and a weighted average switching algorithm is provided when switching is controlled by adopting a mechanical sensor at a low speed and adopting a speed-free sensor at a high speed, and the weighted average switching algorithm comprises motor rotating speed switching and motor angle switching, so that stable transition of the rotating speed and the angle of the motor during high and low speed switching is realized, and overcurrent of the motor is avoided. By adopting the method, stable operation of the long-stator linear motor in a full-speed domain range can be realized, and safe operation of a train is ensured.

The invention relates to the technical field of sensors, and discloses a full-speed-domain position-sensorless control method for a permanent magnet synchronous motor. The full-speed-domain position-sensorless control method for the permanent magnet synchronous motor comprises the following steps: S1, realizing a high-frequency pulsating injection method in a zero-low-speed domain, injecting a high-frequency pulsating signal into a motor system, and extracting rotor position information according to system response characteristics; s2, estimating the position and the speed of a rotor in real time in a medium-high speed domain by adopting a super-spiral sliding mode observer method; and S3, adopting a composite control strategy, and combining the two methods to realize full-speed-domain composite control. According to the full-speed-domain position-sensorless control method for the permanent magnet synchronous motor, the high-frequency pulsating injection method and the super-spiral sliding-mode observer method are combined, position-sensorless high-precision control over the permanent magnet synchronous motor in the full-speed domain is achieved, the control performance is effectively improved, the system cost and complexity are reduced, and the control precision is improved. And the application prospects in multiple fields are widened.

An epicyclic power gear box for a gas turbine engine delivers torque from a low speed shaft to the primary fan. The gear box includes a planet gear and a bearing pin for the planet gear, sun gear and ring gear. The planet gear and bearing pin are arranged so that a clearance between the two is maintained during a takeoff condition for the gas turbine engine.

The invention belongs to the technical field of excavator rotation systems, and particularly relates to an excavator electric rotation system and a control method, the excavator electric rotation system comprises a handle, a tilt angle sensor, a rotation angle sensor, a weighing system, a whole machine controller, a power supply system, a brake resistor, a rotation motor and a brake; wherein the handle and the sensor are connected with an input port of the whole machine controller; the output port of the complete machine controller is connected with the control port of the brake, and the communication port of the complete machine controller is connected with the communication ports of the motor controller and the weighing system; the motor controller is connected with the power supply system, the rotary motor and the brake resistor, and the rotary motor is mechanically connected with the brake and the speed reducer. The acceleration stability in the rotation process is improved, the acceleration stability in the rotation process is improved, the stability in the rotation stopping process is improved, the problem that the regenerative braking force is insufficient when the motor is at a low speed is solved, the application working condition is wider, and the system is more reliable.

The invention discloses a 360 vehicle-mounted around-view camera calibration method and device based on ground texture features, and the method comprises the steps: enabling a camera with calibrated internal parameters to be installed and fixed on a vehicle, measuring the installation position of the camera, controlling the vehicle to go straight at a low speed on a flat and wide ground with certain textures, detecting and matching ground feature point sets of adjacent frames, and carrying out the calibration of a 360-degree vehicle-mounted around-view camera. Calculating the position and attitude change of the vehicle by using the internal reference and the feature points; further calculating 3d coordinates of the ground feature points, and fitting to obtain a ground normal vector; calculating a rotation matrix of a camera coordinate system and a world coordinate system, and calculating multiple groups of vectors by using multiple frames of data to optimize the rotation matrix; and obtaining a top view of each camera by using the rotation matrix and the camera position initial value, collecting feature points of adjacent overlapping areas, and performing position optimization on all cameras of the surround view system. According to the method, calibration auxiliary tools are not needed, a site does not need to be printed in advance, calibration can be achieved only through a flat ground with certain textures, and the possibility of errors caused by personnel operation and measurement is reduced.

Provided are windshield improvements for a low speed vehicle, such as a golf cart. The low speed vehicle windshield protects occupants from UVA and UVB rays, reduces glare, and optimizes optics of the passenger. Further, the windshield has streamline attachment methods with a new windshield profile, and vent arrangements.

The invention provides a switched reluctance motor low-speed rotor position estimation method, and belongs to the technical field of switched reluctance motor control. The method comprises the following steps: firstly, discretizing a winding voltage equation of the switched reluctance motor, obtaining predicted current of each phase through programming calculation and formula recombination of a controller, and acting the predicted current on hysteresis control of a conduction region; secondly, in combination with a partition PWM hysteresis variable-duty-ratio pulse injection method, setting three high-frequency pulses with different duty ratios to be injected into a conduction region, a follow current region and a non-conduction region respectively, and increasing the number of sampling current slope difference values when a switch tube in the conduction region is switched off; and finally, performing logic combination and comparison on the three-phase current slope difference curve generated by calculation to obtain a real-time rotor position. According to the method, the rotor position estimation precision is improved, the rotating speed range is widened, the amplitude of response current in a non-conducting region is limited, negative torque is avoided, and low-speed stable operation of the motor is facilitated.

The invention relates to an ice and snow disaster variable speed limit control method and system based on a friction coefficient, and belongs to the field of intelligent traffic. According to the method, a set of variable speed limit control units are arranged on a road at intervals, and all the variable speed limit control units are in communication connection with a centralized decision-making unit through communication modules; each set of variable speed-limiting control unit detects traffic flow data, meteorological environment data and road condition data of a lane level in real time, uploads the data to the centralized decision-making unit, determines an optimal lane-level variable speed-limiting control scheme and an optimal deicing and snow-removing scheme through a decision-making optimization algorithm, and issues the optimal lane-level variable speed-limiting control scheme and the optimal deicing and snow-removing scheme to the variable speed release module; and the variable speed release module releases a lane level variable speed limit control scheme of a corresponding section, namely the lowest speed limit value, the highest speed limit value, the suggested speed and the like of each lane, and performs deicing and snow removal operation according to the deicing and snow removal scheme so as to ensure road traffic safety in ice and snow weather. The road traffic safety guarantee level is improved through variable speed limiting.

The invention discloses a trencher based on improvement of excavating equipment, which is characterized in that an original excavating working device is detached from an upper body of an original excavator, and a trenching device is additionally arranged on the upper body of the original excavator; the ditching device comprises a supporting arm frame and a ditching chain. The supporting arm frame is connected with the original upper machine body and rotationally provided with a driving wheel set and a tensioning wheel set. The trenching chain is arranged on the driving wheel set and the tensioning wheel set in a sleeving mode so as to conduct continuous trenching operation; the original engine-hydraulic power system is additionally provided with a ditching driving motor, and the ditching driving motor is connected with a driving wheel set; the ditching driving motor realizes rotary driving and stopping actions of the ditching chain through an original movable arm oil cylinder confluence oil way in the original engine-hydraulic power system and is additionally connected with a pilot valve for control; the original left and right track driving oil ways are respectively connected with the small-flow proportional valves, the small-flow proportional valves are respectively connected with the original left and right track driving oil ways in parallel, a small part of hydraulic power is shunted from the original main pump oil way, the trencher is driven to crawl at a low speed during trenching operation, and the trencher can move while trenching during operation.

The invention belongs to the field of control of electric vehicles, and discloses a compatible control device and method for stable micro-motion and quick start of a sightseeing vehicle. A vehicle feedback speed value and an accelerator given speed value are collected in real time; the accelerator given speed value after acceleration rate limiting processing is output as a motor correction speed value; the feed-forward curve processes the accelerator given speed value and the rotating speed deviation value to obtain a motor control signal, and the smaller one is taken as a feed-forward control signal to be input into a speed regulator; after the rotating speed deviation value is adjusted through PI parameters of the speed adjuster, the rotating speed deviation value serves as a compensation control signal to be overlapped with the feed-forward control signal to control the motor, so that when the vehicle runs at a low speed, the feed-forward control signal plays a small role, the smaller PI parameters and the compensation control signal set in the speed adjuster play main roles, and when the vehicle runs stably and needs to be started quickly, the motor is controlled. The feed-forward control signal plays a major role, and the vehicle can be quickly started, so that the vehicle can be quickly started while meeting stable micro-motion.

The invention discloses a permanent magnet synchronous motor extremely-low-speed robust position sensorless control method, device and system. The method comprises the following steps: performing ESO current-disturbance observation on dq-axis current values, voltage reference values and rotor position information at a k moment to obtain an observation current and a q-axis disturbance observation value at a k + 1 moment; the dq-axis current value, the observation current and the dq-axis current reference value at the k moment are observed through a rotor position observer, and the position and the rotating speed of a motor rotor at the k + 1 moment are obtained; adopting a feed-forward compensation method to obtain a q-axis voltage feed-forward value at the k + 1 moment according to the q-axis disturbance observation value at the k + 1 moment and the rotating speed of the motor at the k + 1 moment; and dynamically adjusting a q-axis voltage feed-forward value according to the position of the motor rotor at the k + 1 moment and the q-axis disturbance observation value, and realizing effective suppression of the torque ripple in the low-speed region. According to the method, the robustness and the anti-interference capability of a low-speed region are enhanced while the steady-state performance and the dynamic response of the system are improved.

The invention discloses a loader and a control method and device thereof, the loader comprises an engine, a torque converter and a transmission, and the control method comprises the following steps: acquiring a first external characteristic curve of the engine when the loader is in a normal working condition; when it is determined that the loader is in the slipping working condition, the critical output torque of an engine when the loader slips is obtained; according to the critical output torque and the first external characteristic curve, obtaining a second external characteristic curve of the engine when the loader is in the slipping working condition; and the engine is controlled to rotate based on the second external characteristic curve, so that the engine can reach the critical output torque at the lower rotating speed, and the power consumption of the loading machine under the slipping working condition can be effectively reduced.

The invention discloses an automobile lane changing auxiliary system which comprises a steering lamp operating rod assembly, an electronic control unit, a left rearview mirror module, a right rearview mirror module, a position sensor, a rearview mirror position memory module and an automobile state detection module, and the steering lamp operating rod assembly is arranged on the left side of a steering wheel and provided with a neutral position, a first gear and a second gear; the electronic control unit receives an operating rod signal and outputs a control instruction; the left rearview mirror module comprises a left rearview mirror horizontal rotation actuator and a left rearview mirror lens; the right rearview mirror module comprises a right rearview mirror horizontal rotation actuator and a right rearview mirror lens. Therefore, 0-20-degree adjustment of the rearview mirror is related to the vehicle speed, a blind area is covered at a low speed in a large angle, interference is avoided at a high speed in a small angle, risks are reduced, multi-gear linkage simplifies operation, the rearview mirror returns after being loosened, automatic centering is achieved after lane changing, distraction is reduced, navigation and a corner sensor recognize the road condition, manual reset is not needed, and adaptability is high.

The invention discloses a permanent magnet synchronous motor full-speed-domain position-sensorless hybrid control method and a permanent magnet synchronous motor full-speed-domain position-sensorless hybrid control system, and the permanent magnet synchronous motor full-speed-domain position-sensorless hybrid control method is constructed by taking a permanent magnet synchronous motor nonlinear dynamic system model as a starting point. A hybrid control method combining high-frequency pulsating square wave signal injection under a linear dynamic system model, a rotor polarity judgment and rotor initial position estimation algorithm and an unscented Kalman filtering extension algorithm in an additive noise form under a nonlinear discrete dynamic system model is adopted; and obtaining the optimal estimation observation value of the system state variable in the static, low-speed, medium-speed and high-speed full-speed domain range under the condition that the permanent magnet synchronous motor is not provided with a mechanical position sensor. The optimal estimation observation value is used for compensating and feeding back a permanent magnet synchronous motor drive control system adjusting strategy, disturbance of load torque is improved, the noise amount and disturbance amount introduced by three-phase current measurement are eliminated, and efficient and accurate control operation of the permanent magnet synchronous motor is achieved.

The utility model relates to the technical field of wheel hub motors, and in particular to a brushless DC wheel hub motor; it comprises a wheel hub module, a motor module, a reduction box module, and a built-in electromagnetic brake system module; the motor shaft of the motor module passes through the housing of the reduction box module and is connected with the electromagnetic brake friction plate of the built-in electromagnetic brake system module; the built-in electromagnetic brake system module is also provided with a brake coil, a brake spring, and a brake armature; the spring pops out the brake armature, the brake armature limits the electromagnetic brake friction plate, and the electromagnetic brake friction plate locks the motor shaft of the motor module; after the brake coil is energized, a magnetic brake spring is generated and the brake armature is attracted, the brake armature is separated from the electromagnetic brake friction plate, and the motor shaft of the motor module is unlocked, thereby achieving the effects of low cost, small size, low power consumption, high low-speed torque, large rated output speed range, and high brake sensitivity.

The invention relates to the technical field of mortar detection, and discloses a mortar consistency detection device, which comprises a bottom plate, the top of the bottom plate is fixedly connected with a placing seat, the top of the placing seat is provided with a conical cylinder, the bottom of the conical cylinder is provided with a hexagonal hole, the top of the placing seat is fixedly connected with a fixing rod, and the fixing rod is fixedly connected with the bottom of the conical cylinder. The top of the fixing rod is fixedly connected with a supporting ring, the supporting ring makes contact with the outer wall of the conical barrel, a flattening mechanism is arranged on the containing base, and the flattening mechanism comprises a low-speed motor, a rotating rod, a hexagonal block, a fixing block, a first rotating shaft, a fixing plate, an adjusting bolt, a limiting groove, a lifting plate, a limiting rod, a sliding block and a flattening plate. Through mutual cooperation of the low-speed motor, the rotating rod, the hexagonal block and the hexagonal hole, the conical cylinder is driven to rotate at a low speed, so that various components of mortar are distributed more uniformly in the cylinder, abnormal stress of a cone caused by non-uniform components of the mortar is avoided, and a detection result is more accurate.

To provide a radiator unit for a saddle-riding vehicle or ATV, having advantage in suppressing the short circuit flow of air and improving radiation performance.SOLUTION: When viewed from a lower side, which is a direction orthogonal to a direction in which a radiator 22 and a radiator fan 24 are aligned, a short circuit flow prevention plate 26 covering a gap S1 between the radiator 22 and the radiator fan 24 is provided on the radiator 22. At a place where the short circuit flow prevention plate 26 is provided, air flow, that is, short circuit flow, passing through the gap S1 between a dorsal surface 22B of the radiator 22 and the radiator fan 24 from around the radiator 22 and flowing into the radiator fan 24, can be prevented, which is made advantageous for increasing an air volume passing through the radiator 22 when a vehicle is stopped or traveling at low speed and improving radiation performance of the radiator 22.SELECTED DRAWING: Figure 4

The invention provides a steering-by-wire vehicle variable transmission ratio design method and system based on a fuzzy neural network, and belongs to the field of vehicle steering-by-wire. According to a fixed gain method, the steering angle transmission ratio is too small at a low speed, and the sensitivity is low at a high speed; the existing intelligent algorithm excessively depends on the experience of a designer and the quality of a data sample. The method comprises the following steps: establishing a closed-loop driver-vehicle system, designing a multi-target evaluation method by using a quadratic cost function of a vehicle dynamic state, and obtaining a data relationship between a vehicle ideal variable transmission ratio characteristic and a vehicle longitudinal speed and a steering wheel angle; a nonlinear control model is established through a fuzzy RBF network, and a globally optimal solution is obtained based on nonlinear model learning. The robustness of the control system is improved, the stable and reliable transmission ratio can be provided under various vehicle conditions, and the problem that a steering system is light and flexible is solved, so that the experience feeling of a driver under various vehicle conditions is improved, and meanwhile the operation stability and safety of the vehicle are improved.

The utility model belongs to the technical field of motors, and relates to a magnetic-adjustable back-wound motor structure, which comprises a stator iron core, the stator iron core comprises an annular stator yoke part, a plurality of stator inner teeth are uniformly distributed on the inner wall of the stator yoke part, and the outer surface of the stator yoke part is respectively provided with a stator outer tooth corresponding to each stator inner tooth; groove-shaped adjustable flux winding upper positioning grooves and adjustable flux winding lower positioning grooves are symmetrically formed in the two sides of the stator outer teeth, adjustable flux windings are wound on the adjustable flux winding upper positioning grooves and the adjustable flux winding lower positioning grooves of the stator outer teeth respectively, and the two sides of coils of the adjustable flux windings are located in the adjustable flux winding upper positioning grooves and the adjustable flux winding lower positioning grooves respectively. The turns of the windings on the two sides are equal; according to the utility model, by arranging the adjustable magnetic windings on the outer stator teeth, the magnetic field modulation effect generated after the adjustable magnetic windings are electrified is utilized to increase and demagnetize the internal magnetic field of the motor and adjust the air-gap magnetic field, thereby realizing transmission of large torque at a low speed or flux-weakening speed expansion at a high rotating speed.

The invention relates to the technical field of vehicles, in particular to a vehicle driving warning sound generation method and device, equipment and a storage medium. Environment bottom noise data is obtained through real-time collection and analysis, and a frequency band possibly generating a masking effect on the generated warning sound is judged according to the data; in particular, the system recognizes the frequency bands influenced by the masking effect according to the spectral characteristics of the environmental noise, and increases the volume of the frequency bands in a targeted manner to ensure that the warning sound can be effectively transmitted to pedestrians, and in addition, the system also can give the warning sound to the pedestrians according to the actual driving scene of the vehicle. According to the method, the most appropriate warning sound frequency band and gain parameters can be intelligently selected to adapt to different acoustic environments, such as an underground garage or an open parking lot, so that the pedestrian warning effect when the electric vehicle runs at a low speed is remarkably improved.

The present invention provides a method for controlling the automatic start of a commercial vehicle AMT, including a control state model and the jump conditions of the control state model. Through the collaborative control of the vehicle control system, the transmission control system, the engine control system and the handle control system, when the vehicle is in the D / R gear position, releasing the foot brake and not stepping on the accelerator, the transmission control system controls the clutch to automatically engage, and the vehicle travels stably at a low speed. When the vehicle encounters other harsh working conditions with large driving resistances such as a large slope, in order to avoid the risk of engine stalling, the engagement depth of the clutch is adjusted in real time to ensure the power response and driving smoothness of the vehicle's automatic start condition, and enhance the driver's control performance.

The utility model provides a secondary aluminum waste gas purifying device which comprises a purifying tank, and a filtering and purifying assembly is arranged in the purifying tank. The circulating pump can convey an alkaline solution in the liquid storage cavity into the spraying disc through the liquid outlet pipe and disperse and spray the alkaline solution downwards to be in contact with the secondary aluminum waste gas for purification, and the residue filtering screen plate can filter the sprayed alkaline solution, so that the circulating pump is prevented from being easily blocked in the use process; a low-speed motor drives a transmission vertical rod to rotate through a transmission shaft, a driving bevel gear and a driven bevel gear, the transmission vertical rod can drive scattering blades and a follow-up plate to rotate at a low speed together, and in the process, the rotating scattering blades can repeatedly scatter an alkaline solution sprayed out of a spraying disc, so that the alkaline solution is fully atomized; and the follow-up plate rotating at a low speed can drive the silica gel scraping plate to rotate to scrape part of impurities blocked by the upper end face of the residue filtering net plate, so that the cleaning period of the residue filtering net plate is prolonged.

The invention provides a road adhesion coefficient estimation method based on an adaptive slip speed tire model. The method comprises the following steps: establishing a vehicle dynamics model; estimating a tire force based on vehicle dynamics; estimating the vehicle speed by using an unscented Kalman filtering algorithm based on singular value decomposition; a tire model based on the slip speed is constructed, and normalized tire force is calculated according to the tire model; estimating a road adhesion coefficient by using an unscented Kalman filtering algorithm based on singular value decomposition; according to the self-adaptive slip speed tire model provided by the invention, the problem of denominator singularity of a current slip rate-based tire model at a low speed and the limitation of a fixed stiffness parameter are overcome, so that the estimation precision and the response speed of the road adhesion coefficient are improved.

The utility model provides a corrosion-resistant leaching tank for preparing high-purity lithium carbonate, which comprises a leaching processing tank, a stirring component is arranged in the leaching processing tank, a liquid guide component is arranged at the upper end of a protective cover, and in the preparation process of the high-purity lithium carbonate, a low-speed motor drives a rotating vertical shaft to rotate through a driving bevel gear and a driven bevel gear; a rotating vertical shaft can drive a stirring cross rod and a stirring vertical rod to rotate at a low speed to stir lithium ore powder in the leaching processing tank, and meanwhile, a fluorine lining adjusting valve is opened, so that acid liquor in a liquid storage tank is dispersed and discharged downwards through a connecting pipe, a liquid guide cavity, a communicating cavity and a plurality of liquid discharging through holes; and moreover, the rotating liquid feeding rod can also enable the discharged acid liquid to be scattered in a wider range, the acid liquid is prevented from intensively flowing to a local area to form deposition, so that the acid liquid can be quickly and uniformly mixed with the lithium ore powder in the leaching processing tank, and the mixing leaching efficiency of the lithium ore powder and the acid liquid is higher.

The invention discloses a congestion relieving method and system for a highway, a vehicle and equipment. The highway congestion relieving method comprises the steps that the speed of a vehicle and a lane where the vehicle is located are obtained; judging whether the vehicle speed meets the lowest speed limit requirement of the lane or not; under the condition that the vehicle speed does not meet the minimum speed limit requirement of the lane, whether the lane is the lane with the minimum minimum speed limit or not is judged; and if the lane is not the lane with the minimum speed limit, a speed-up prompt or a slow lane change prompt is triggered. By the adoption of the method and device, when the vehicle runs on the expressway at the tortoise speed, a driver can be effectively reminded to increase the speed or change to the slow lane, so that the vehicle running at the tortoise speed is prevented from influencing normal running of other vehicles, the probability of occurrence of road congestion is reduced, and the driving safety is improved. The probability of occurrence of rear-end collision and other accidents caused by turtle-speed driving is avoided, and the driving experience on the expressway is effectively improved.

The invention discloses a motor control switching method and a control circuit thereof, and the method comprises the steps: determining a real-time motor control mode, collecting a system current and a system voltage based on the real-time motor control mode, and calculating the rotating speed of a motor based on the system current and the system voltage; the motor rotating speed is compared with a preset speed threshold value, motor control modes are switched based on a comparison result and a real-time motor control mode, and the motor control modes comprise square wave control and FOC control. Smooth switching of motor control modes is achieved by monitoring the rotating speed of the motor in real time and comparing the rotating speed according to the preset speed threshold value. Square wave control is adopted at a low speed to improve efficiency, and FOC control is switched at a high speed to improve control precision and dynamic response. By collecting system current and system voltage, the rotating speed of the motor is calculated, smooth transition is conducted in the switching process, and it is ensured that the motor stably operates under the large-load working condition within the full-speed range.

The invention relates to the technical field of traffic safety protection, and discloses a tunnel portal flexible blocking system which comprises a water curtain generation system which is arranged on a portal frame of a tunnel portal, is composed of an efficient spray head, a water storage tank, a liquid level sensor and a controller and is used for rapidly forming a flexible water curtain barrier to slow down the vehicle speed and providing visual warning. The water source is taken from a tunnel leakage water discharge system and ensures the water quality through a filtering device; the flexible barrier gate system is installed near a tunnel entrance and is of a structure that an aluminum alloy core column wraps a foam material. A flexible water curtain barrier can be rapidly formed in emergency through the water curtain generation system, and the effects of blocking vehicles and preventing further accident expansion are achieved. The automatic design enables the water curtain barrier to be formed within second-level time, the water curtain barrier can be closed at a low speed in emergency, vehicles are flexibly intercepted, and damage to the vehicles and system equipment is reduced.