371 results about "Torque regulation" patented technology

The invention discloses an engine control method, device and equipment and a storage medium, and relates to the technical field of vehicle control, and the engine control method comprises the steps that when a target vehicle has an engine starting requirement, a target rotating speed difference and a target torque change rate are obtained; determining a target synchronization state according to the target rotating speed difference and the target torque change rate; when the target synchronization state is a synchronization success state, gear switching is carried out according to a target gear instruction and a speed regulation and torque regulation instruction, and a gear switching state is obtained; and when the gear switching state is a gear switching completion state, an engine of the target vehicle is started. In the running process of the EV (electric vehicle), the engine needs to be started in advance for transition in the scene that large ramps possibly exist and power is insufficient, the pure electric mode EV gear is transited to the ECVT gear, the engine is started, driving is conducted through a driving motor and the ECVT at the same time, and the driving performance of the whole vehicle is improved.

The invention relates to the technical field of electric vehicles, in particular to an electric vehicle parking motor torque adjusting method. The problems that an existing electric automobile parking system is insufficient in parking force control precision, lagged in response and low in energy consumption efficiency under complex working conditions are solved. According to the method, a multi-dimensional vehicle running state, a driver instruction and environment sensing data are collected in real time, a vehicle-environment coupling dynamic model is established and updated in real time, then an adaptive model predictive control (AMPC) strategy is utilized, the future movement trend of a vehicle is predicted based on the dynamic model and a target parking demand, and the vehicle-environment coupling dynamic model is established and updated in real time. And the optimal torque instruction of the parking motor in the current control period is optimized and calculated, and the parking motor is driven to generate corresponding torque. High precision, high adaptability, high safety and high stability of parking torque adjustment can be achieved, the energy efficiency is effectively improved, the service life of parts is effectively prolonged, and the intelligent level is enhanced.

The invention relates to an engine braking stepless regulation method, device and equipment and a medium, and belongs to the technical field of engine braking. The method comprises the steps that a negative torque request and basic driving data sent when a vehicle is braked are obtained, and the required negative torque is determined according to the negative torque request; according to the basic driving data and the required negative torque, the engine braking starting state is determined; when the engine braking starting state is starting, and engine braking of the vehicle does not meet the required negative torque, a pneumatic supercharger is adjusted, and first engine braking torque is obtained; when the first engine braking torque meets the required negative torque, stepless adjustment of engine braking is completed, and the braking effect can be improved through engine braking and adjustment of a pneumatic supercharger; the engine braking torque of the vehicle is controlled according to the required negative torque, continuous and variable torque adjustment can be carried out, and then stepless adjustment of engine braking is achieved.

The invention discloses a cooperative control method for conversion of torque control and rotating speed control of an engine and a generator and a medium. The method comprises the following steps: calculating available recovery torque of a generator, and requesting an engine to load reserve torque by a vehicle control unit; activating an engine rotation speed control flag bit, an engine control rotation speed mode and a generator control torque mode; determining a target rotating speed and a target torque, further determining a generator torque filtering rate, and respectively controlling and adjusting the rotating speed and the torque; and exiting the engine rotation speed control flag bit, the engine control torque mode and the generator control rotation speed mode. By increasing the reserve torque of the engine, the torque adjusting capacity of the engine is improved, the engine and the generator are cooperatively controlled, and engine speed fluctuation is reduced.

The invention provides an atmosphere push plate furnace driving system based on servo motor frequency conversion control. The atmosphere push plate furnace driving system comprises a real-time detection module, a multi-mode control module, a strategy generation module and a system optimization and evaluation module. The method comprises the following steps: analyzing collected real-time data of different targets, identifying a current working condition stage of a system, switching to a corresponding control mode according to the identified working condition stage so as to generate a corresponding control strategy, dynamically adjusting the rotating speed and the torque of a motor according to the control strategy, and carrying out optimization test and evaluation on the system; a real-time load monitoring and feedback mechanism is adopted, a control algorithm and a rotating speed and torque adjusting strategy are applied, effective vibration suppression measures are combined, the dynamic response characteristics of the servo motor can be fully utilized, the rotating speed and torque of the servo motor can be adjusted in real time according to load changes, and start-stop impact and mechanical vibration of the atmosphere pusher furnace are remarkably reduced.

Provided in the present invention is a gravity-free spring roller blind controller. The gravity-free spring roller blind controller comprises a torque adjustment assembly and a torsion spring connecting rod assembly. The torque adjustment assembly comprises a bracket, a torsion spring mounting seat, a guide sleeve, and a roller blind sleeve. A one-way torsion spring is sleeved on a mounting shaft of the torsion spring mounting seat, the guide sleeve is further rotatably sleeved with a torque adjustment knob, the guide sleeve is provided with a first flange, and a second flange is provided on the torque adjustment knob. The first flange reversely pushes the one-way torsion spring so that the one-way torsion spring is locked tightly onto the mounting shaft. According to the present invention, the torque of the torsion spring on the torsion spring connecting rod assembly is increased or decreased by forwardly or reversely rotating the second flange.

The invention discloses a vehicle braking control method and device, a new energy vehicle and a storage medium, and relates to the technical field of new energy vehicles. The method comprises the steps that under the condition that an electric braking function of the vehicle is activated, an electric braking initial torque is determined; determining current driving intention information based on the driving operation information for the vehicle; the driving intention information is acceleration intention information or deceleration intention information; based on a correction strategy corresponding to the driving intention information, the electric braking initial torque is corrected, and an electric braking target torque is obtained; different driving intention information corresponds to different correction strategies; and the motor output torque of the vehicle is adjusted according to the electric braking target torque so as to control vehicle braking. By adopting the method, the safety of the electric braking process of the vehicle can be improved.

The invention discloses a vehicle control method and system, a vehicle and a readable storage medium, and the method comprises the steps: determining the torque reduction torque of a slipping wheel when the vehicle is in a differential steering working condition and the vehicle has the slipping wheel; and the torque of the coaxial wheels is adjusted according to the torque reduction torque. According to the method, when the vehicle is determined to be in the differential steering working condition, the differential state of the vehicle is classified, the wheel slipping problem under the differential working condition is subjected to identification scheme optimization, and different driving torque control logics are used, for example, a coaxial control strategy is adopted for slipping wheels, so that the wheel slipping problem is solved. A control strategy is formulated according to the working condition of reverse slipping of the wheels on the inner side, it is guaranteed that reverse slipping of the wheels can be recognized in time, the use scene of the differential function is expanded, the phenomena of high-speed slipping of the wheels, posture deflection of a vehicle body and the like of the vehicle are avoided, and the reliability of the differential function of the vehicle is improved.

A driving torque adjustment method and device, a vehicle (200), and a storage medium. The driving torque adjustment method comprises: detecting whether a mass calculation condition of a vehicle (200) is sufficient; if the mass calculation condition of the vehicle (200) is sufficient, calculating the current mass of the vehicle (200) in real time; on the basis of the current mass of the vehicle (200), calculating a torque correction coefficient; and on the basis of the torque correction coefficient and the required torque of the vehicle (200), calculating a driving torque of the vehicle (200), and controlling a driving system (50) of the vehicle (200) on the basis of the driving torque. In this way, the current mass of the vehicle (200) is calculated, the torque correction coefficient is calculated on the basis of the mass, and then the torque can be adjusted on the basis of the torque correction coefficient, and torque compensation can be performed on the driving system (50), so that the vehicle (200) having the changed mass and the vehicle (200) having the calibrated reference mass can keep the same acceleration while the stroke for the driver stepping on the accelerator pedal and the torque remain unchanged.

The invention discloses a pivot steering control system and method based on a four-wheel steering driving automobile and the automobile, and belongs to the technical field of automobiles. The in-situ steering control system obtains the state information of a vehicle through the state observation module, and the algorithm decision-making module receives the state information sent by the state observation module and then carries out decision-making calculation output processing according to the state information. And a pivot steering control decision containing a wheel steering angle adjusting instruction and a wheel output torque adjusting instruction is obtained, so that the four wheels are controlled to deflect by specific directions and angles through the control execution module, driving is conducted according to the deflection angles of the vehicles in the specific directions, and pivot steering control over the vehicles is achieved. The in-situ steering control system can dynamically adjust steering angles and torque distribution of the four wheels according to actual driving working conditions, the accuracy and response speed of in-situ steering control are improved, and the vehicle can accurately achieve in-situ steering according to an expected posture.

The utility model provides a torque adjusting structure of a hydraulic retarder, and belongs to the technical field of hydraulic retarders. The oil cooler comprises a middle cover, a rear cover and an oil cooler body, the rear cover is connected with the middle cover and the oil cooler body through fastening screws, oil through holes are correspondingly formed in the rear cover and the oil cooler body, throttling ring installation grooves are formed in the side wall, close to the oil through holes, of the rear cover, and throttling rings are arranged in the throttling ring installation grooves. The throttling ring mounting groove is located at the end of the oil through hole and communicates with the oil through hole, and a throttling ring is arranged in the throttling ring mounting groove; by means of the design that a traditional throttling piece is changed into the throttling ring, use of a locking screw is avoided, the throttling ring can be directly arranged in a specially-designed installation groove in a buckled mode, the assembling and maintaining process of the device is simplified, and the throttling ring can be replaced more rapidly and conveniently; and when the throttling ring needs to be replaced, only the oil cooler needs to be disassembled, the process of disassembling and assembling the throttling piece is omitted, and the damage probability of the device is reduced while more convenience is achieved.

The invention relates to the technical field of torque calculation, in particular to a torque adaptability regulation and control method and system for an electric power-assisted bicycle, and the method comprises the steps: receiving a torque regulation instruction, starting a system regulation unit based on the torque regulation instruction, collecting a side-sway angle and a side-sway angular velocity, calculating transmission delay, and if the transmission delay is not in a delay range, starting the system regulation unit; if the transmission delay is within the delay range, screening the transmission data packet set to obtain a standard data packet set and an over-limit data packet set, adjusting the over-limit data packet set to obtain an adjusted data packet set, and obtaining an integrated data packet set based on the standard data packet set and the adjusted data packet set; and if not, calculating an external interference estimated value, calculating a side-sway angular acceleration by using the external interference estimated value, calculating a side-sway torque and an offset torque, calculating a regulation and control torque according to the side-sway torque and the offset torque, and completing torque adaptive regulation and control according to the regulation and control torque. According to the invention, the regulation and control speed and accuracy of torque adaptive regulation and control can be improved.

The invention relates to the technical field of vehicles, and discloses a gear shifting control method of a double-electric-drive-axle vehicle, the vehicle, a medium and a program product. The method comprises the steps that according to the current vehicle driving state, a target gear corresponding to a first electric drive axle is obtained; according to the target torque reduction time, the first electric drive axle is controlled to reduce the torque, and meanwhile, according to the driver demand torque and the actual output torque of the first electric drive axle, the second electric drive axle is controlled to compensate the torque; the first electric drive axle is controlled to conduct reverse torque adjustment; acquiring a target rotating speed, and controlling the rotating speed of the input shaft of the first electric drive axle to reach the target rotating speed; and according to the target torque increasing time, the first electric drive axle is controlled to increase the torque, so that gear shifting control over the first electric drive axle is achieved. According to the scheme of the embodiment, the vehicle power can be guaranteed in the gear shifting process, meanwhile, the gear shifting smoothness of the whole vehicle is guaranteed, and the vehicle use experience of a user can be improved.

The utility model relates to the technical field of anti-torque adjustment, in particular to an anti-torque adjusting mechanism which comprises a rack, an adjusting assembly, a connecting assembly and a mounting assembly. The adjusting assembly comprises a plurality of speed reducers, motors, ball screws and a moving seat, the speed reducers are fixedly connected with the rack and located on the front face of the rack, the front face of each speed reducer is fixedly connected with one motor, the opposite side of each speed reducer is connected with one ball screw, and the moving seat is located on the front face of the rack. The outer side of each ball screw is fixedly connected with one moving seat, the connecting assembly is connected with the ball screws, the mounting assembly is connected with the rack, and the problem of controllable adjustment of air gap errors of the undulator under different motion air gaps is solved.

The invention relates to the technical field of automatic control, in particular to a chip device for integrated control of an electric workover rig. According to the method and the device, through fine analysis of the job data, dynamic adjustment of the task priority in the job stage is realized, so that calculation resource allocation is more accurate, and the execution efficiency of the key task is improved. In the stress optimization process of the drill column, real-time monitoring on the lateral deviation trend is introduced, additional load calculation is conducted in combination with the stratum rebound influence, the overall stress of the drill column is more balanced, and the problem of abnormal stress concentration caused by lateral deviation is solved. The torque adjusting mechanism is dynamically optimized based on the stress distribution condition of the drill bit, it is ensured that the torque adjusting direction is matched with the stress trend of the drill bit, abnormal abrasion caused by uneven stress of the drill bit is reduced, and the drilling stability is improved. Trend analysis under various bit pressure conditions is adopted in drilling depth prediction, and in combination with a stratum permeability mapping relation, bit pressure adjustment is more reasonable, and the risk of sudden change of drill bit load is reduced.

Embodiments of this application provide example torque adjustment methods, apparatuses, and vehicles. One example method includes obtaining a requested torque value. A first intervention torque value is determined based on a wheel acceleration of a vehicle and a vehicle acceleration of the vehicle. Based on the requested torque value and the first intervention torque value, the vehicle is controlled to perform energy regeneration.

An anti-skid control method and system for a vehicle, and a vehicle. The method comprises: an electronic stability controller of a vehicle determining a target rotational speed of a driving component corresponding to a slipping wheel and transmitting the target rotational speed to a vehicle control unit (101); the vehicle control unit determining a target torque of the driving component on the basis of the target rotational speed and an actual rotational speed of the driving component, and transmitting the target torque to a drive system controller (102); and the drive system controller adjusting an output torque of the driving component on the basis of the target torque, so as to stabilize the vehicle (103).

The invention discloses a control method for controlling the follow-up speed change of a drip irrigation disc of a seeder based on Beidou speed measurement. The control method comprises the following steps: S1, collecting and preprocessing position information and speed information of a tractor; s2, inputting the preprocessed data into a fusion calculation unit, and executing space-time weight calibration; s3, inputting the fusion speed sequence into a speed prediction network, extracting multi-scale features, and generating a speed guide feature map; s4, generating a target rotating speed instruction according to the mapping function and operation parameter modulation; s5, inputting a target rotating speed instruction to a motor control unit, and generating a current signal through dual-channel torque regulation and control; s6, a motor is driven to rotate the drip irrigation disc, the actual rotating speed is collected, and an error sequence is constructed; and S7, inputting the error sequence into a calibration module, generating a correction parameter to update a current signal, and realizing synchronous control. According to the invention, high-precision synchronous control of the drip irrigation disc on the speed of the tractor is realized, and the drip irrigation consistency, the response speed and the operation stability are improved.

A vehicle mode switching method, apparatus, and system, a vehicle, a computer program, and a readable medium, relating to the technical field of vehicle control. When a vehicle meets a mode switching condition of switching from a power split mode to a direct drive mode, a clutch (102) is kept in an engaged state, and torque adjustment is performed on an engine (101) and a first motor (103), so that when a first synchronizer (105) meets a torque condition, rotation speed adjustment can be performed on the first motor (103), and when the first synchronizer (105) meets a rotation speed condition, the first synchronizer (105) can be controlled to switch from a power split gear to a combined gear, so as to switch the vehicle from the power split mode to the direct drive mode. A gear shifting operation of the first synchronizer (105) is smoothly completed without disengaging or engaging the clutch (102), so that the engine (101) can quickly output torque while the duration of mode switching is shortened, thereby improving the power response performance of the vehicle during mode switching.

The invention provides a variable-diameter belt pulley capable of adjusting torque, and relates to the field of belt pulleys. The variable-diameter belt pulley capable of adjusting the torque comprises a pulley body and a power input shaft, a pulley outer diameter mechanism is arranged on the surface of the pulley body, the pulley outer diameter mechanism comprises a belt groove in sliding connection with the pulley body, and a torque adjusting mechanism is arranged in the middle of the pulley body. The torque adjusting mechanism comprises a first connecting disc, a second connecting disc and a threaded ring, and the middle of the threaded ring is in threaded connection with an adjusting rotary disc. According to the variable-diameter belt pulley capable of adjusting the torque, a first connecting disc and a second connecting disc abut against each other, a power input shaft drives a threaded ring to rotate, then a pulley body and a belt groove drive a belt to be transmitted, the meshing strength between the first connecting disc and the second connecting disc is adjusted by adjusting a rotary disc, and then torsion of the belt pulley is adjusted; and the power equipment is prevented from being damaged when the load is too large, and the operation stability and safety of the power equipment are improved.

The invention discloses a vehicle torque control method and device, a storage medium and a vehicle. The method comprises the steps that torque demand information and vehicle state information of a target vehicle are obtained, the torque demand information comprises a target torque condition and current period demand torque, the current period demand torque is used for controlling a motor to conduct torque output in the current period, and the vehicle state information at least comprises a load signal and a slope signal; determining a torque gradient model of the target vehicle based on the vehicle state information; and performing torque adjustment of at least one period on the demand torque of the current period by using the torque gradient model until the demand torque of the current period meets the target torque condition. By means of the technical scheme, it is ensured that the vehicle torque is adjusted to the target torque within a limited period, negative influences on vehicle stability and energy efficiency caused by sudden torque changes when the torque is adjusted at a time are avoided, and the running stability and comfort of the torque vehicle are ensured.

The present invention belongs to the field of wind power generation system control, and discloses a fan torque regulation system based on actual aerodynamic coefficients, which includes a fan blade information collection module, an aerodynamic coefficient calculation module, a power regulation module, and a host computer module. The power regulation module includes a torque adjustment unit and a control unit connected to each other. The fan blade information collection module is connected to the aerodynamic coefficient calculation module, and the host computer module and the aerodynamic coefficient calculation module are respectively connected to the torque adjustment unit. The fan blade information collection module is used to identify the geometric shape data of the fan blades. The aerodynamic coefficient calculation module is used to calculate the corresponding actual aerodynamic coefficients according to the geometric shape data of the fan blades. The host computer module is used to input information on the required change in fan power. The torque adjustment unit calculates the actual torque required by the fan based on the actual aerodynamic coefficients, the fan motor speed information, and the information on the required change in fan power. The control unit adjusts the fan torque based on the real-time torque required by the fan.

The invention belongs to the technical field of automatic control, in particular to a tractor tilling depth automatic control device based on torque adjustment, and provides the following scheme that the tractor tilling depth automatic control device comprises a shaft seat and two rotating arms, the two rotating arms are fixedly connected to the top of the shaft seat, an engine is fixedly connected to the top of the shaft seat, and a lower rotating shaft is rotatably connected to the middle of the shaft seat; the two ends of the lower rotating shaft are located on the two sides of the shaft seat respectively and fixedly connected with coulters distributed at equal intervals, and the lower rotating shaft is in transmission connection with the output end of the engine. According to the device, angle monitoring of the rotating arm is achieved through the relative positions of the copper columns and the copper plates, when the rotating arm deflects to the set angle, the device can achieve automatic adjustment, the copper plates are installed on the two sides of the insulating plate, and therefore the device can adjust the inclination angle of the rotating arm in the two deflection directions of increasing and decreasing, tilling depth control steps are simple, and operation is convenient. And parts are easy and convenient to adjust and maintain, and higher popularization value is achieved.

The invention discloses a stepless speed change device which comprises a bearing, a center shaft, a cone-shaped body, a torque adjusting mechanism, an electric control system and a transmission device, and the center shaft is movably arranged in the bearing; the conical body is rotatably arranged on the central shaft; the torque adjusting mechanism is movably arranged on the central shaft and is movably connected with the inner wall of the conical body; the electric control system is connected with one end of the central shaft; the transmission device comprises a first transmission mechanism and a second transmission mechanism, and the first transmission mechanism and the second transmission mechanism are rotatably arranged on the two sides of the conical body respectively. Therefore, the design of the sliding power transmission wheel ensures stable and continuous speed change, improves efficiency and smoothness, reduces vibration and noise, prolongs the service life, an electric control system meets various speed change requirements, a torque adjusting mechanism can adjust torque according to requirements, the application range is widened, wear resistance, corrosion resistance and fatigue resistance of the transmission are enhanced through different materials, and the transmission is suitable for large-scale popularization and application. And long-term reliability and stability are ensured.

The electric drive assembly comprises a drive motor, the periphery of a motor shaft is in transmission connection with a first gear set, the first gear set is in transmission connection with a planetary gear train so as to transmit torque to a sun gear in the planetary gear train, and one end of the sun gear is matched with a first-gear gear through a spline; one end of a planet carrier in the planetary gear train, which is in transmission fit with the sun gear, is fixedly connected with a second-gear gear; the synchronizer comprises a gear sleeve and a gear ring, the gear sleeve is arranged on the gear ring in a sliding mode in the axial direction, and the sliding path of the gear sleeve at least comprises three working positions which are the position engaged with the first-gear gear, the position engaged with the second-gear gear and the position disengaged from the two-gear gear; the gear sleeve is in transmission connection with a second gear set, and the second gear set is in transmission connection with the differential mechanism. The compact structure advantage of torque adjustment of the planetary gear train and the efficient advantage of gear adjustment of the synchronizer are combined, so that the driving assembly is high in structure integration degree, and the adjustment process is accurate and rapid.

The invention discloses a transverse movement control system and method based on rear wheel steering, a controller and a vehicle, and belongs to the technical field of vehicles. The transverse movement control system obtains state information of a vehicle through a state observation module, and after an algorithm decision module receives the state information sent by the state observation module, decision calculation output processing is conducted according to the state information, so that a transverse movement control decision containing a wheel steering angle adjusting instruction and a wheel output torque adjusting instruction is obtained. Therefore, the front wheels and the rear wheels are controlled by the control execution module to deflect by a specific angle in the transverse movement direction in the opposite directions and are driven reversely, and transverse movement control over the vehicle is achieved. The transverse movement control system can dynamically adjust steering angles and torque distribution of front and rear wheels according to actual driving working conditions, the accuracy and response speed of transverse movement control are improved, and the vehicle can accurately transversely move along an expected track.

A torque wrench may include a head having a driving member configured to be operably coupled to a socket, a handle, a lever arm operably coupled to the head and the handle at respective opposing ends thereof, a torque adjuster configured to enable a torque setting of the torque wrench to be adjusted and an adjustment channel which may be disposed between the handle and the torque adjuster. A locking member may be disposed within the adjustment channel to block the torque adjuster from changing the torque setting.

A vehicle anti-slip control method and system, a vehicle and a storage medium, relating to the technical field of vehicles. The method comprises: acquiring an actual rotating speed of a motor in a vehicle; determining a target rotating speed of the motor; on the basis of a rotating speed deviation value, generating a torque adjustment signal; when the frequency of the torque adjustment signal is greater than or equal to a safety frequency, inputting the rotating speed deviation value into a notch filter to obtain a corrected rotating speed deviation value; and on the basis of the corrected rotating speed deviation value, generating an updated torque adjustment signal, and when the frequency of the updated torque adjustment signal is smaller than the safety frequency, adjusting the actual rotating speed of the motor to the target rotating speed. Therefore, the smoothness of a vehicle is improved.

The invention relates to the technical field of intelligent massage equipment control, and provides a fascia gun adaptive frequency adjustment and muscle relaxation intensity control method and system. A motor rotation frequency range and a corresponding output torque adjustment coefficient are obtained by receiving a pressure value, collected by a pressure sensor, of contact between a massage head and a human body, an electromyographic signal sensor collects an electromyographic signal of a target muscle group, and an acceleration sensor collects fascia gun motion posture data; according to the rotating frequency range of the motor, determining a target adjusting frequency in a preset safe frequency interval, generating a motor driving control signal according to an output torque adjusting coefficient, and controlling the motor to operate at the target adjusting frequency through a motor driving circuit; if the electromyographic signal sensor continuously collects the electromyographic signals of the target muscle group in a periodic weakening trend, the rotating frequency of the motor is reduced, the output pressure is reduced, and progressive muscle relaxation intensity adjustment is formed. According to the invention, a complete technical system for self-adaptive control of the fascia gun is constructed.

The invention discloses a vehicle control method and a vehicle, and the vehicle control method comprises the following steps: when determining that the vehicle meets a preset condition, controlling an electronic parking brake system of the vehicle to release; in the releasing process of the electronic parking braking system, the hydraulic braking system is controlled to provide first preset braking force; and after the electronic parking braking system is released, the crawling torque of the vehicle is obtained, and the braking force output by the hydraulic braking system is adjusted according to the crawling torque. In the releasing process of the electronic parking braking system, the braking force is provided through the hydraulic braking system to keep the vehicle static, and after the creeping torque is established, the braking force output by the hydraulic braking system is adjusted through the creeping torque, so that the phenomenon that the vehicle slides when starting on a small hill can be prevented, and the service life of the vehicle is prolonged. And thus, the comfort of drivers and passengers can be improved.