50 results about "Brake response time" patented technology

The invention discloses an in-use elevator brake safety performance detection method, relates to the technical field of special equipment elevator detection, and is used for solving the technical problems of related test methods and risk category research and judgment in brake evaluation in accordance with GB / T-42615 Safety Evaluation Standards for In-use Elevator. The in-use elevator brake safety performance detection method comprises the following steps of brake response time measurement, brake synchronism measurement and action voltage measurement of an in-use elevator brake. Wherein the measurement of the braking response time is divided into two working conditions, one working condition is that the elevator ascends to the upper part of the stroke without load to stop, and the other working condition is that the car is loaded with 1.25 times of rated load to downwards run to the lower part of the stroke to stop; it is suggested that no-load ascending braking is carried out firstly, and then a 1.25-time rated load descending braking test is carried out.

The invention discloses an AGV safety control method for intelligent warehousing, and relates to the technical field of intelligent warehousing, and the method comprises the following steps: constructing a global three-dimensional load distribution diagram of an automatic guided vehicle in real time through the fusion of a laser radar and an inertial measurement unit, and outputting a mass distribution matrix; based on the mass distribution matrix, millimeter wave Doppler tomography is superposed, the barycentric coordinates are dynamically corrected, and a corrected mass distribution matrix is obtained; and inputting the corrected mass distribution matrix into a braking dynamic prediction engine, and generating a prediction curve of an adaptive braking distance and braking response time in combination with online inversion estimation of a ground friction coefficient. Through the digital twin simulation and micro-pulse pre-braking strategy, the risk of inertial collision and cargo overturning is effectively reduced, a storage scheduling system is controlled in parallel, path reconstruction and driving priority dynamic adjustment are achieved, and global safety and efficient scheduling of intelligent storage are guaranteed.

The invention discloses a front and back vehicle and road information identification system based on machine learning, and belongs to the technical field of vehicle safety identification, and the system employs a high-precision binocular camera and an improved YOLOv5m target detection model to realize all-weather real-time monitoring of obstacles around a vehicle, and effectively covers a traditional visual blind area. Through a dynamic distance measurement and speed tracking algorithm, the system can pre-judge the potential collision risk in advance, the traffic accident rate caused by a view blind area is reduced, and the traffic flow efficiency is optimized through an in-vehicle and out-vehicle collaborative prompt mechanism. The in-vehicle display screen visually marks dangerous targets through the augmented reality technology, and the time for distraction of a driver to study and judge road conditions is shortened; and the multicolor LED lamp strip at the tail of the vehicle transmits the front real-time road condition to the rear vehicle, so that the overall braking response time of the vehicle team is shortened. The risk of serial rear-end collision can be reduced, meanwhile, fuel oil waste caused by sudden braking is avoided, and the system has economical efficiency and environmental protection value.

The invention relates to a clamping force constraint backstepping sliding mode control method for an electronic mechanical braking system, and belongs to the related technical field of new energy automobile control. The method comprises the following steps of: establishing a state space model of the system by considering the nonlinear characteristic of the electronic mechanical braking system, and reasonably simplifying the state space model into a strict feedback form; a time-varying tangent barrier Lyapunov function (BLF) containing an error integral term is constructed, an exponentially decayed time-varying function is used as a constraint boundary of a clamping force tracking error, the integral term is introduced to eliminate a steady-state error caused by unmodeled dynamics, and the output constraint performance and tracking precision of a system are ensured; on the basis, a control law is designed by combining a backstepping method and non-singular fast terminal sliding mode control, and fast and accurate tracking of the braking clamping force is achieved; and proving the system stability based on the Lyapunov stability theorem. According to the invention, the braking response time and the clamping force control precision of the electronic mechanical braking system can be effectively improved.

The invention discloses a commercial vehicle braking system and a vehicle. The commercial vehicle braking system comprises a vehicle frame, a trailer valve support, a rear fender support, a tail cross beam and an air cylinder unit. The core is that the air cylinder units are arranged in a dispersed manner: a first air cylinder is arranged on the side surface or below a trailer valve bracket and is close to a front axle brake chamber; the second air cylinders are symmetrically arranged on the rear fender supports on the two sides, and the space of a fender groove is utilized and the second air cylinders are close to a rear axle brake chamber. And the third air reservoir is accommodated in the inner cavity of the tail cross beam forming the semi-closed box body structure. By means of distributed, integrated and internally-wrapped optimized layout of the air cylinders, the ground clearance and trafficability of a vehicle are remarkably improved, precious space on the two sides of a vehicle frame is released to install a large oil tank, the braking response time is optimized due to the fact that the length of a braking pipeline is shortened, and the whole vehicle layout is more reasonable and efficient.

The invention provides a gear and rack climbing type ship lift adopting a balance winding drum for safe fortification and an operation method of the gear and rack climbing type ship lift, relates to the field of ship lifts, and aims to solve the problems of main engine arrangement and water leakage safety fortification of a high-water-head large-tonnage ship lift. The ship lift comprises a self-bearing ship chamber structure, gear and rack driving mechanisms distributed on side wing platforms, a balance winding drum device at the top of a tower column, a balance weight system and a butt joint locking / jacking device. The ship chamber driving mechanism is driven to ascend and descend through meshing of a gear and a rack, the balance winding drum device is connected with the ship chamber and the balance weight system through a steel wire rope, weight balance is achieved, and locking is achieved through an accident brake during water leakage. The butt joint device resists loads through frictional contact and mechanical self-locking. According to the invention, the manufacturing and mounting problems of the super-large winding drum are avoided, space conflicts are solved, a three-level protection mechanism is constructed, the braking response time is less than or equal to 0.5 second, the locking reliability is 100%, and the device is suitable for navigation of ships with 200m-level water heads and 5000 tons.

The invention provides an anti-pinch control method, device and system for an electric tail door and a vehicle, and relates to the technical field of vehicle control. The method comprises the following steps: receiving radar original point cloud data generated by a millimeter wave radar sensor in an obstacle sensing module; receiving tail gate motion data sensed by a tail gate motion sensor in the electric tail gate actuating mechanism; filtering the radar original point cloud data to generate preprocessed data; obstacle identification and classification are carried out on the preprocessed data through an obstacle identification and classification model, and the obstacle type is determined; determining the position, motion data and distance of the obstacle according to the preprocessed data; determining a critical distance according to the movement data of the obstacle, the movement data of the tail gate and predefined braking response time; according to the obstacle type, the obstacle distance and the critical distance, an anti-pinch control instruction is determined; and an anti-pinch control instruction is sent to an electric tail gate executing mechanism. The anti-pinch control sensitivity is improved, and the safety is improved.

The invention provides a pneumatic valve device, a pneumatic brake system and a commercial vehicle. The pneumatic valve device comprises a first air pressure port used for receiving air source pressure of a lower pressure value; the second air pressure port is used for transmitting trailer braking pressure; the third air pressure port is used for outputting trailer brake control air pressure; the first air pressure port is connected with the third air pressure port through a working cavity of the relay valve; the fourth air pressure port is used for receiving the air source pressure with the higher pressure value; the control end of the energy supply valve is connected with the first air pressure port, an air inlet of the energy supply valve is connected with the fourth air pressure port, an air outlet of the energy supply valve is connected with the second air pressure port, the energy supply valve is constructed to make the air inlet and the air outlet communicated when the pressure of the control end of the energy supply valve is larger than an opening threshold value, and the opening threshold value is smaller than the first pressure value. The air source pressure with the higher pressure value can be introduced into the trailer braking system, the energy storage capacity of the trailer braking system is improved, the trailer braking response time can be shortened, and the whole vehicle braking efficiency is improved.

The utility model discloses a centralized electric drive bridge and vehicle, wherein, the centralized electric drive bridge includes axle, motor, first brake component and first speed reducer, and motor, first brake component and first speed reducer are integrated in the radial side of axle, and first brake component exports the braking force to axle through locking the input end or output end of first speed reducer, the utility model discloses the centralized electric drive bridge of the present application, by integrating motor, first brake component and first speed reducer in the radial side of axle, form compact power module, reduce the space occupation, through the input end or output end of locking first speed reducer of first brake component, compared with prior art, can significantly prolong the service life of motor, and, shorten the brake force transmission chain, improve the brake response time, can greatly improve the heavy load, heavy -duty vehicle ramp parking and emergency brake safety.

The invention relates to an elevator safety clamp braking response time testing device and a testing method thereof, belongs to the technical field of elevator accessory detection, and aims to solve the problems that the initial state of an existing testing device is difficult to control and no failure protection exists. A baffle of the bearing part horizontally slides to bear and release the test plate, a bilateral synchronous power assembly drives the baffle to reduce lateral disturbance when the test plate is released, a protection part comprising a buffer plate and a buffer assembly is arranged, and the buffer assembly is matched with a compression spring through an inclined sliding hole to convert vertical impact into buffer resistance. According to the device, initial test conditions are accurately controlled, failure protection is provided, test repeatability and safety are improved, and the device is suitable for the field of elevator accessory detection and the like.

The invention relates to the technical field of automobiles, and particularly discloses an electric back door control method and device and a vehicle. The method comprises the steps that it is determined that a target vehicle is in a traction state, and the target vehicle is a traction vehicle; acquiring current traction working condition data corresponding to the target vehicle; based on the current traction working condition data, opening parameters of the electric back door are determined, and the opening parameters comprise at least one of an anti-pinch force threshold value, braking response time, the opening speed of the back door and the opening degree of the back door; and based on the opening parameters, the electric back door is controlled to be opened. By collecting the traction working condition data of the traction vehicle under different working conditions, the opening parameters of the electric back door of the traction vehicle are determined by using different methods, so that the opening of the electric back door is controlled, and the function safety and the user experience in the traction state are balanced.

The present application relates to the field of rail vehicle braking technology, and discloses a power actuation control method in rail vehicle braking, comprising: collecting a stator current sequence of a braking torque generation unit, calculating a first-order forward difference value to identify a load stiffness jump characteristic and determine a brake shoe contact position, locking the current effective value corresponding to the brake shoe contact position as a clamping current reference, adjusting the output torque compensation mechanism gap in response to the brake shoe contact position, and locking the integral path in the anti-slip adjustment unloading stage to maintain the stator current at the clamping current reference, wherein the present application uses electromagnetic parameter surface layer mutation to accurately offset the transmission gap of the mechanism, realizes physical quasi-synchronization of the electric command and mechanical action, suppresses the mechanism rollback phenomenon in the anti-slip stage, guarantees the real-time performance of the braking force reconstruction, and shortens the braking response time.

The utility model relates to the technical field of brake performance testing, in particular to a vehicle EBS brake response time testing system which comprises an electric control spiral line, brake response time testing equipment and a pressure sensor. One end of the electric control spiral line is divided into a first branch and a second branch; the end part of the first branch is connected with an EBS electric control interface of a tractor of a tested vehicle, and the other end of the electric control spiral line is connected with an EBS electric control interface of a trailer of the tested vehicle, or the first branch is kept in an unconnected state, and the other end of the electric control spiral line is connected with the EBS electric control interface of the tractor of the tested vehicle; the end part of the second branch is connected with the brake response time testing equipment; the pressure sensor is installed on a brake chamber test port of a trailer of the tested vehicle, and the pressure sensor is connected with the brake response time test device.

The embodiment of the invention relates to the technical field of vehicles, and discloses a vehicle control method and device, a vehicle and a storage medium. The method comprises the steps that first lightening information corresponding to a high-mount stop lamp on a front vehicle is obtained; according to the first lightening information, the first brake opening degree of the front vehicle is determined; and according to the first braking opening degree and the preset braking opening degree, the vehicle is controlled to conduct braking action. By applying the technical scheme, the braking intention of the front vehicle can be quickly sensed, the braking response time under the vehicle following scene can be shortened, the rear-end collision risk is reduced, and the implementation cost is lower than that in the prior art.

The application discloses an accelerator pedal anti-misoperation brake auxiliary control system and method, which comprises the following modules: a gap pre-elimination module, which controls the synchronous starting of four-wheel EMB caliper motors when an activation flag position is monitored, eliminates the working gap between the brake caliper and the brake disc, and maintains zero-gap adhesion; an intermittent brake reminding module, which synchronously applies intermittent short brake deceleration, and transmits tactile feedback to the driver through three stages; a speed reduction control module, which synchronously starts the steady-state pre-speed reduction control, and maintains the target longitudinal deceleration during the short brake interval; and a logic judgment and exit module, which judges whether to stop the short brake according to the accelerator pedal opening degree signal, and judges whether to restore the default working gap according to the brake pedal stroke and other controller brake requests. The application solves the problems of the existing anti-misoperation technology, such as response lag and poor reminding effectiveness, and greatly shortens the brake response time through the cooperation of gap pre-elimination and reminding speed reduction, and the driving smoothness and system compatibility are taken into account.

The application provides a safety risk early warning method and system based on brake performance evaluation, belonging to the field of vehicle brake performance evaluation and safety technology, and the method comprises the following steps: acquiring brake system operation data, vehicle motion state data, environment perception data and external scene data of a vehicle; calculating a current brake performance evaluation index based on the brake system operation data and the vehicle motion state data; the current brake performance evaluation index comprises a brake response time, a brake distance and a brake stability index; performing feature fusion processing on the brake response time, the brake distance and the brake stability index to obtain a brake performance feature vector; in response to any current brake performance evaluation index being less than a corresponding preset performance index threshold, calculating a safety risk level based on the brake performance feature vector, the environment perception data and the external scene data through a safety risk model; and executing a corresponding risk early warning strategy according to the safety risk level.

The utility model provides a stacking machine with a multi-brake resistor management function, and relates to the technical field of stacking machines. Through the arrangement of the brake management switch, the first coil and the second coil, the brake management switch changes the electrical connection mode of the first coil and the second coil, and different brake response time is achieved; in other words, through simple circuit topology changes (such as parallel connection or series connection of the first coil and the second coil), two operation modes can be provided for the stacking machine body under the condition of low cost, and the controller selects different operation modes according to detection of actual conditions so as to control the braking time, so that the braking efficiency is improved. And the shaking and other negative conditions of the stacking machine caused by higher instantaneous torque generated by a stacking machine main body due to too fast speed reduction or too short speed reduction time of a large inertia load are reduced.

An embodiment of the present invention provides a charging driving control method, device, and storage medium. The method includes: obtaining a first response time of a power supply vehicle, wherein the first response time is the braking response time of the power supply vehicle; determining a third response time based on the first response time and the second response time of a vehicle to be charged, wherein the second response time is the braking response time of the vehicle to be charged; and when the vehicle to be charged establishes a charging connection with the power supply vehicle, controlling the vehicle to be charged and the power supply vehicle to travel in coordination using the third response time as a driving time parameter. By using the third response time as the driving time parameter for the coordinated driving of the vehicle to be charged and the power supply vehicle during charging, coordinated driving of the power supply vehicle and the vehicle to be charged is achieved, while ensuring driving safety during the coordinated driving process.

The invention relates to an internal breathing type air cylinder for a heavy truck, and solves the problems that the air pressure is low after full-stroke braking of continuous five-time treading, the braking response time becomes poor after the air pressure is reduced, and the braking distance becomes long. Comprising a telescopic centering shaft (1), a spring (2), a diaphragm stabilizing plate (3) and a breathing diaphragm (4), the breathing diaphragm (4) is fixed on the inner wall of the air cylinder and divides the air cylinder into an independent driving energy storage cavity (5) and a breathing cavity (10), the diaphragm stabilizing plate (3) is fixed on the breathing diaphragm (4) in the breathing cavity (10), the spring (2) is connected between the diaphragm stabilizing plate (3) and the air cylinder, and the diaphragm stabilizing plate (3) is fixed on the breathing cavity (10). The air cylinder driving energy storage cavity (5) and the breathing cavity (10) are respectively provided with an air inlet and a detection port, and the driving energy storage cavity (5) is further provided with an air outlet and a drain outlet (11). According to the internal breathing type air cylinder with the pressurizing function, the air pressure of the air cylinder after full-stroke braking of continuous five-time treading can be increased, so that the response time of a braking system is prolonged, the braking distance is shortened, and the driving safety is improved.

The utility model relates to a drive-by-wire brake valve group for an inspection vehicle, and belongs to the technical field of brake systems, in particular to the technical field of brake systems of anti-explosion inspection vehicles. The hydraulic brake system special for the anti-explosion inspection vehicle is constructed by arranging the priority valve, the pressure compensation valve, the proportional pressure reducing valve, the high-pressure selection valve and other valve structures, hydraulic rubber pipes of the foot valve, the brake valve and the brake can be reduced, the driving space is released, shorter brake response time can be achieved, and the service life of the anti-explosion inspection vehicle is prolonged. The brake distance is reduced, the safety is improved, and the oil leakage phenomenon of a cab is avoided. In addition, when one energy accumulator fails, the arrangement of the high-pressure selection valve ensures that the other energy accumulator can still work normally, and the safety is further improved.

This utility model relates to the field of safety engineering and emergency protection technology, and discloses an insulated lifting platform for live-line work on high-voltage transmission lines. It includes a chassis, a compression mechanism on the top center of the chassis, lifting rods fixedly connected to the left and right sides of the top of the chassis, a platform fixedly connected to an adjacent side of the two lifting rods, a protective mechanism on the top of the platform, two buffer blocks fixedly connected to the top of the chassis at their bottoms, and multiple Z-shaped rods fixedly connected to the top of the lifting rods at their bottoms. The left and right sides of the platform are slidably connected to adjacent sides of the two lifting rods. In this utility model, the air inside the telescopic column is rapidly compressed into the air compressor, causing adsorption blocks one and two to quickly adhere to the outer wall of the lifting rods. The pneumatic force rapidly triggers braking, significantly shortening the braking response time and improving platform safety.

This invention provides a method, device, system, and vehicle for anti-pinch control of an electric tailgate, relating to the field of vehicle control technology. The method includes: receiving raw radar point cloud data generated by a millimeter-wave radar sensor in an obstacle sensing module; receiving tailgate motion data sensed by a tailgate motion sensor in an electric tailgate actuator; filtering the raw radar point cloud data to generate preprocessed data; identifying and classifying obstacles in the preprocessed data using an obstacle recognition and classification model to determine the obstacle type; determining the position, motion data, and distance of the obstacle based on the preprocessed data; determining a critical distance based on the obstacle's motion data, tailgate motion data, and a predefined braking response time; determining an anti-pinch control command based on the obstacle type, obstacle distance, and critical distance; and sending the anti-pinch control command to the electric tailgate actuator. This invention improves the sensitivity of anti-pinch control and enhances safety.

A dynamic self-adaptive control method and system for a non-coal mine track inspection robot comprises the steps that S1, track abnormal working conditions are sensed in real time, S2, driving system self-adaptive control is conducted, S3, catastrophe response decision making is conducted, and corresponding actions are executed according to trigger conditions: when B8 is equal to 1, electromagnetic locking braking and sound-light alarm are triggered, and the electromagnetic locking braking response time is smaller than or equal to 70 ms; through multi-dimensional technical innovation, an efficient, safe and intelligent technical scheme is provided for non-coal mine track inspection, and the method has important significance in promoting technical progress in the field of non-coal mine automatic inspection.

The application discloses a kind of life-cycle-oriented adaptive brake compensation control method, device, equipment and storage medium, it is related to vehicle brake control technical field, comprising: through real-time acquisition brake system operating state parameter by vehicle-mounted multi-source sensor, brake system operating state parameter includes brake motor real-time working current, brake hydraulic circuit pressure, each wheel real-time wheel speed and brake response time difference;According to the cumulative running mileage of vehicle and cumulative brake load integral, determine brake system wear index;According to brake system wear index, compensate and adjust proportional integral differential control gain to reference brake torque, obtain compensation brake torque and dynamic proportional integral differential gain;According to compensation brake torque and dynamic proportional integral differential gain, generate brake control instruction and send to brake execution system, so that vehicle maintains brake response consistency and torque output accuracy in whole life cycle.

The invention discloses an early warning method for dynamic vehicle wake display and lateral collision avoidance. The early warning method comprises the following steps: 1) collecting traffic data; traffic data of a main vehicle and surrounding vehicles are collected in real time through microwave radar arrays and road side units (RSU) which are arranged on a tunnel and a bridge at intervals; 2) dynamically evaluating the collision risk; (3) arc-shaped LED units are arranged at equal intervals at the lane line; (4) side wall LED lamp strips are arranged on the outer side wall of the lane at equal intervals, and the visual approximation effect is generated by adjusting the light-emitting length L and the interval D of the side wall LED lamp strips; and (5) early warning is triggered according to the risk grade judgment, calculated in real time, of the main vehicle. According to the method, in the aspect of longitudinal risk control, dynamic wake display enables the braking response time of rear vehicles to be shortened, and the rear-end collision accident rate in the tunnel is remarkably reduced; lateral deviation early warning is linked with optical warning through a millimeter wave radar, the lateral deviation detection error is controlled within a certain range, and side collision accidents of a curve scene can be effectively reduced.

The utility model provides an electric control mechanical brake for eliminating transmission clearance, which comprises a caliper body, a middle shell connected with the caliper body, an outer shell connected with one side of the middle shell far away from the caliper body, a motor connected with one side of the middle shell close to the caliper body, a motor shaft of the motor penetrating through the middle shell, and a driving gear connected with one side of the motor shaft close to the outer shell. The side, close to the outer shell, of the middle shell is connected with an idle gear and a planetary gear mechanism. The driving gear is meshed with the idle gear, and the idle gear is meshed with the planetary gear mechanism. The idle gear is coaxially connected with a compensation device, and the compensation device eliminates the meshing clearance between the idle gear and the driving gear. The compensating device is arranged at the idle gear to eliminate the meshing clearance, so that the whole gear mechanism is compact in structure, the braking response time is shortened, the braking response is sensitive, the influence of the gear clearance on the braking distance is avoided, and the driving safety is improved.

The invention provides an electronic mechanical braking system and a working method thereof. The system comprises a tractor electronic mechanical braking system and a trailer electronic mechanical braking system, wherein the tractor electronic braking system is provided with a tractor EMBS central electric control module, a tractor motor control module, a tractor parking control module and a brake pedal control module; the tractor parking control module is electrically connected with the tractor EMBS central electric control module and the tractor motor control module. The brake pedal control module is electrically connected with the tractor EMBS central electric control module and the tractor motor control module. The trailer electronic braking system is provided with a trailer EMBS central electric control module, a trailer motor control module and a trailer parking control module. And the trailer control module is electrically connected with the EMBS central electric control module. Brake response synchronization of the tractor and the trailer is achieved; the braking response time is shortened; the braking distance is effectively reduced and the driving safety is improved.

The invention provides a safety risk early warning method and system based on brake performance evaluation, and belongs to the technical field of vehicle brake performance evaluation and safety, and the method comprises the steps: obtaining brake system operation data, vehicle motion state data, environment perception data and external scene data of a vehicle; calculating a current braking performance evaluation index based on the braking system operation data and the vehicle motion state data; the current brake performance evaluation indexes comprise brake response time, brake distance and a brake stability index; performing feature fusion processing on the braking response time, the braking distance and the braking stability index to obtain a braking performance feature vector; in response to the fact that any current brake performance evaluation index is smaller than a corresponding preset performance index threshold value, calculating a safety risk level through a safety risk model based on the brake performance feature vector, the environment perception data and the external scene data; and executing a corresponding risk early warning strategy according to the security risk level.

The invention discloses a pre-filling control method, device and equipment for triggering hydraulic braking and a storage medium. The method comprises the steps that whether a current vehicle enters a pre-filling triggering area or not is judged; when the current vehicle enters the pre-filling triggering area, the gradient change rate and the target value of pre-filling force are calculated; executing rising control or falling control of the pre-filling force according to the gradient change rate and the target value, and performing safety amplitude limiting on the executed pre-filling force to obtain a target final pre-filling force; the braking response time can be effectively shortened, the braking distance is reduced, meanwhile, the braking impact degree is reduced, and the response speed, the control precision and the driving smoothness of a braking system are remarkably improved. The system reliability is improved, the vehicle type universality is enhanced, the service life of a braking system is prolonged, the energy utilization efficiency is optimized, and all-working-condition safe operation is achieved.

The invention discloses a test bench and a test method for brake response time of an EMB assembly, and the test bench comprises a caliper which is provided with a filler block, the caliper can drive the filler block to move, and the filler block can move to be close to a brake disc so as to clamp the brake disc; the interior of the environment bin is used for providing environment simulation conditions required by testing for the calipers; the fixing tool is arranged in the environment bin, and the fixing tool is used for installing and fixing calipers; the vibration mechanism is used for driving the fixing tool to vibrate so as to drive the calipers to vibrate; the detection mechanism comprises a plurality of force sensors, the plurality of force sensors are arranged between the contact parts of the calipers and the filler block, and when the brake disc is clamped by the filler block, the force sensors can detect the pressure of the calipers acting on the filler block. The brake response time can be accurately calculated, and the reliability and authenticity of the test are improved.