36 results about "Velocity feedback" patented technology

The invention relates to the technical field of electro-hydraulic integrated driving, in particular to a hydraulic synchronous control system and method based on traveling wave and magnetic field composite driving, the system comprises a plurality of hydraulic cylinders, and each hydraulic cylinder comprises a piston rod assembly and a cylinder barrel; the piston rod assembly comprises a metal push rod on the inner layer, a three-phase winding module arranged around the metal push rod on the middle layer and a lining barrel on the outer layer. Each hydraulic cylinder corresponds to one pressure sensor, one displacement sensor and one controller. The cylinder barrel serves as a secondary conductor, eddy current is generated through traveling wave magnetic field induction, and axial thrust is generated. In a no-load state, the controller switches the current direction to generate auxiliary oil absorption thrust; during loading, current parameters are dynamically adjusted according to displacement, pressure and speed feedback, and synchronous compensation and speed regulation are achieved. The linear motor has the characteristics of high thrust density of a hydraulic system and quick response of the linear motor, and is suitable for high-precision engineering machinery and aerospace hydraulic actuating mechanisms.

The invention discloses a control method of an energy accumulator oil supply hydraulic servo system of a shipborne helicopter mooring device, which belongs to the field of mechanical hydraulic control and comprises the following steps: establishing a mathematical model of the energy accumulator oil supply hydraulic servo system; based on the position of a helicopter probe rod, the speed track in the capturing process of a mechanical claw is planned; a smooth speed feedback signal is obtained through a tracking differentiator; generating a feed-forward control quantity by a feed-forward controller; designing an error active disturbance rejection controller comprising a feedback compensator and an extended state observer based on the mathematical model, and generating an error adjustment signal; and the feedforward control quantity and the error adjusting signal are synthesized, the parameters of the error active disturbance rejection controller are adjusted, a final control instruction is formed to drive a hydraulic servo system, and the mechanical claw tracks the planned speed track. The problem of flow-pressure nonlinearity in the oil supply process of the energy accumulator is effectively solved, the capturing speed tracking precision of the mechanical claw is improved, capturing impact is reduced, and the quick mooring device is suitable for helicopters of different tonnages.

An adaptive control method for offshore cranes without requiring velocity feedback, in which parameters of an offshore crane system are obtained, and a three-dimensional dynamic model of an offshore crane system is constructed based on ship's roll and pitch motions; a total energy function is constructed based on the three-dimensional dynamic model, and an energy change is described according to a change rate of a total energy of the offshore crane system; based on the three-dimensional dynamic model, auxiliary variables are constructed to replace a velocity signal of a state variable in a controller; based on an inverse trigonometric saturation function and the auxiliary variables, an adaptive controller without requiring velocity feedback is constructed; and the offshore crane system is controlled based on the adaptive controller for control to realize positioning and sway suppression. An adaptive control system is also provided.

The invention discloses a control method of a sound wave electric toothbrush, which comprises the following steps: outputting an initial PWM (Pulse Width Modulation) signal to drive a sound wave motor according to set working parameters of a brush head, and when the brush head vibrates, the working parameters of the brush head comprise the vibration amplitude and vibration frequency of the brush head; when the brush head vibrates, the working parameters of the brush head comprise the vibration amplitude and the vibration frequency of the brush head; working parameters of the brush head at the current moment are obtained, and working parameters of the sound wave motor at the current moment are calculated; according to the working parameters of the sound wave motor at the current moment, whether the brush head works normally or not is judged, and when abnormity occurs, the working parameters of the sound wave motor are adjusted according to the abnormity reason, so that the brush head works according to the set working parameters of the brush head. The position of the brush head is obtained through the angle sensor, current collection is combined, a closed-loop control system of torque estimation and angular velocity feedback is achieved, output of electric brush power can be dynamically adjusted, and the control precision and the adaptive capacity are improved.

The application discloses a linear electromagnetic actuator integrating sensing and executing, which comprises a rotor, a guide rail and a stator; the guide rail is installed on the stator; the guide rail is provided with a movable groove, and the rotor can move in the movable groove. The stator comprises a stator base plate, an inductor coil and a driving coil; the inductor coil is integrated on the back of the stator base plate, and the driving coil is installed on the front of the stator base plate. The inductor coil and the magnetically conductive rotor base plate form an inductor system, when the rotor moves under the action of the driving coil, the inductance will periodically change with the position of the rotor. The position detection of the motor can be carried out based on the periodic change of the inductance, and the speed feedback control of the electromagnetic actuator is facilitated.

The application discloses a glue coating tension closed loop control method combining tension and speed feedback, relates to the technical field of glue coating tension control, and is used for solving the problems of product coating quality reduction and increased thickness fluctuation influence, collecting the winding diameter data of the rear driving roller in the winding stage, calculating the winding diameter growth rate and judging whether the tension prediction mechanism is entered, when the tension prediction mechanism is entered, detecting the front and rear driving roller linear speeds and the winding motor current, calculating the speed deviation characteristics and the same direction judgment value to predict the tension change state and judge whether the tension correction stage is entered, in the tension correction stage, collecting the tension data and the floating roller stroke data of the current winding section, fusing to generate the speed correction factor, adjusting the rear driving roller linear speed according to the speed correction factor, monitoring the coating thickness through the laser thickness gauge, calculating the thickness fluctuation coefficient to judge whether the tension prediction mechanism is entered again, and effectively inhibiting the thickness fluctuation.

A control method and system for constant-speed rotation of a tank body of a concrete mixing truck belong to the technical field of control of concrete mixing transport equipment, and the method comprises the following steps: collecting the rotation speed of the tank body, change data of an electronic throttle, the working pressure of a hydraulic system, the concrete material level and the running speed of the truck; parameters of a PID algorithm are corrected based on electronic throttle change data, and correction factors are set in combination with the working pressure of a hydraulic system, the concrete material level and the vehicle running speed; the corrected PID algorithm judges the working condition according to the change data of the electronic throttle and the rotating speed of the tank body, in the acceleration working condition, the load increasing trend of the hydraulic system is pre-judged in advance, and the adjusting amount of the displacement of the hydraulic pump is increased; when the rising value of the rotating speed of the tank body is larger than a preset threshold value, adjusting intervention is conducted in advance; and the hydraulic driving system is controlled according to the adjusting instruction, and the adjusted rotating speed of the tank body is fed back. The rotating speed control precision of the tank body is improved, and the concrete rejection rate is reduced.

The application provides a signal processing method and device, electronic equipment and a storage medium. The signal processing method comprises the following steps: acquiring a speed feedback signal used for indicating the running speed of a mechanical arm; calculating a filtering duration according to the speed feedback signal; performing filtering processing on a position feedback signal used for indicating the position of the mechanical arm and acquired within the filtering duration, to acquire a filtered feedback signal used for indicating the target position of the mechanical arm. The present scheme can avoid the situation of alarm due to the excessive tracking error of the mechanical arm.

The invention provides a collision protection system and method for a servo control device, and a computer readable medium, which can limit a collision peak force within a range in which damage is not caused even in a high-speed mode, can realize flexible buffering, and can improve system stability. The collision protection system for the servo control device comprises a servo motor which drives the servo control device based on a torque control signal and outputs position feedback through a servo motor encoder; a servo drive device that generates a speed feedback on the basis of a differential value of the position feedback, and outputs a torque control signal to the servo motor on the basis of a reverse command torque when a collision occurs to the servo control device; and a collision protection device that generates a reverse command torque on the basis of the position feedback, the speed feedback, and the servo motor characteristics, and in a time range corresponding to the number of reverse torque duration cycles generated on the basis of the number of command position execution cycles corresponding to the servo drive device and the servo motor. The reverse command torque is supplied to the servo drive device.

This invention discloses a wave-damping wave tank system and control method, relating to the field of wave testing technology. The system includes a constraint device, a water tank, a wave-generating device, a wave-damping device, and a control system. The wave-generating and wave-damping devices are configured to have identical structures. The control system is configured to apply different control strategies to the wave-generating and wave-damping devices, and calculates the target thrust command based on the displacement and velocity feedback of the wave-generating and wave-damping floats. The wave-damping device applies an external control force to the floats. This invention, by setting up a wave-generating and wave-damping device, relies on the wave-generating device to generate waves by performing reciprocating linear motion in the vertical direction to induce oscillation in the working fluid. The wave-damping device employs an active wave-damping algorithm with nonlinear restoring force compensation, effectively improving wave-damping efficiency under large amplitude conditions.

The invention discloses a linear induction motor speed sensorless control method based on a vector sum, and belongs to the technical field of segmented linear induction motor control, and the method comprises the steps: introducing a virtual secondary method according to a segmented linear induction motor mathematical model, and constructing an equivalent mathematical model based on a virtual secondary vector sum; based on the constructed equivalent mathematical model, stator current and rotor flux linkage under a two-phase static coordinate system are selected as state variables to design a sliding-mode observer; the method comprises the following steps: acquiring stator voltage and stator current signals of a motor in real time, taking the current signals as input of a sliding mode observer, taking current observed by the observer as output, and constructing a sliding mode control rate by using an error between a current observation value and an actual measurement value so as to reconstruct motor back electromotive force; integrating the back electromotive force signal to obtain a rotor flux linkage estimation value, and further calculating rotating speed information; and forming a closed-loop control system comprising an equivalent mathematical model, a sliding-mode observer and speed feedback.

The application provides a singular point processing method and system of a hydraulic mechanical arm based on speed feedback, which comprises the following steps: modeling the joint angle rate change of the hydraulic mechanical arm according to an exponential function; introducing a nonlinear particle swarm parameter optimization algorithm to obtain an upper limit value of a damping factor for the established model; obtaining the required damping factor based on the upper limit value of the damping factor, and then obtaining a Jacobian matrix according to the required damping factor and an instruction end speed, and finally obtaining an improved joint angle speed based on the Jacobian matrix.

The six-degree-of-freedom adaptive active-passive composite spatial electromagnetic array damper belongs to the technical field of precision vibration isolation, and utilizes six sets of electromagnetic vibration isolation dampers arranged in a Stewart manner between a connecting upper plate and a base plate to generate low-frequency high-damping and high-frequency low-damping characteristics in six degrees of freedom, thereby effectively and omnidirectionally isolating micro-vibration interference of different frequencies. Each set of electromagnetic vibration isolation damper is constructed by 4n (n≥1, n∈N + ) layers of equal-section magnetic rings arranged in an axial array and vertically magnetized between adjacent layers to construct a high-damping excitation magnetic field, and in real time responds to changes in an external excitation frequency, precisely controls the size and direction of a coil current through a speed feedback control method, dynamically adjusts a damping force to adapt to different working conditions, and ensures optimal vibration isolation effect. The adaptability and stability of the adaptive active-passive composite spatial electromagnetic array damper enable it to still maintain high vibration isolation performance in a multi-degree-of-freedom and frequency diversified vibration environment, thereby providing protection for the stable operation of precision instruments and equipment.

Large precision micro-vibration isolation adaptive active-passive composite space electromagnetic array damping control device belongs to the field of vibration isolation technology, adopting 4n (n≥1, n∈N + ) layers of equal-cross-section magnetic rings are arranged in an axial array and the adjacent layers are magnetized perpendicularly, forming coaxially nested inner and outer permanent magnet arrays, thereby constructing a high-magnetic-density excitation magnetic field around the conductor plate. The conductor plate produces a strong damping effect relative to the movement of the magnetic field. When the external excitation frequency changes, the current in the coaxially nested coils outside the conductor plate is precisely regulated by speed feedback, and the damping force is dynamically adjusted. In low-frequency micro-vibrations, it exhibits high damping characteristics, effectively reducing the vibration transmission rate; in high-frequency micro-vibrations, it exhibits low damping characteristics, achieving efficient attenuation of vibration interference. This active and passive composite damping control strategy enhances the adaptability and stability of large-scale precision micro-vibration isolation and its vibration isolation performance in complex vibration environments.

The invention discloses a robot collision detection method and device, and the method comprises the following steps: controlling a robot to continuously run for at least a first threshold time under the standard working condition of simulating the actual operation, and collecting process data; calculating a difference value between motor rotating speed feedback and speed given, a difference value between observation torque and torque feedforward and a difference value between position instruction speed and speed feedback according to the collected process data, and amplifying the difference values according to a set proportion to serve as difference parameters for representing normal operation and a collision state for judging the occurrence of collision; and the obtained difference parameters are written into a robot servo control system and are used for judgment logic of robot internal collision detection. The method has the advantages that the collision detection parameters suitable for the characteristics of the robot are obtained according to the actual operation characteristics of the robot, and the problem that universal parameters are poor in adaptability is solved.

The invention discloses a gluing tension closed-loop control method combining tension and speed feedback, relates to the technical field of gluing tension control, and is used for solving the problems that the quality of a product coating is reduced, and the influence on thickness fluctuation is increased. Calculating a rolling diameter increasing rate and judging whether a tension prediction mechanism is entered or not, and when the tension prediction mechanism is entered, detecting linear speeds of front and rear driving rollers and current of a rolling motor, calculating a speed deviation characteristic and a same-direction judgment value so as to predict a tension change state and judging whether a tension correction stage is entered or not; tension data of a current coiling section and floating roller stroke data are collected and fused to generate a speed correction factor, the linear speed of a rear driving roller is adjusted according to the speed correction factor, the coating thickness is monitored through a laser thickness gauge, a thickness fluctuation coefficient is calculated to judge whether to enter a tension prediction mechanism again or not, and thickness fluctuation is effectively restrained.

The application discloses a flexible opening and closing control method of an electromagnetic valve based on speed feedback and belongs to the field of electromagnetic valve control. Different driving voltages are respectively used to drive each stage of the controlled electromagnetic valve, and each driving voltage is connected to the controlled electromagnetic valve through switching of a switching switch. A magneto-electric vibration speed sensor is installed on the controlled electromagnetic valve, and the magneto-electric vibration speed sensor converts the vibration signal of the controlled electromagnetic valve into an electric signal reflecting the moving speed of the valve core. The moving speed of the valve core is detected in real time through the magneto-electric vibration speed sensor, and the speed feedback controller is fed back, so that the starting time and the ending time of the negative voltage loading of the opening movement and the starting time and the ending time of the high voltage loading of the closing movement can be accurately controlled, the deceleration of the opening and closing movement of the electromagnetic switch valve is realized, and flexible opening and closing are realized.

The application discloses an angle active control system based on a mass damper in the technical field of active vibration control, which comprises a controlled structure, an angle vibration sensor arranged on the controlled structure, the angle vibration sensor being capable of detecting angle vibration information of the controlled structure, a mass damper arranged on the controlled structure, an internal vibration sensor arranged on a mass block of the mass damper, the internal vibration sensor being capable of detecting linear vibration information of the mass block in a control direction, and a controller, which is in electrical signal connection with the angle vibration sensor, the internal vibration sensor and the mass damper, and is capable of outputting a driving signal for controlling the action of the mass damper to the mass damper according to the received angle vibration information and linear vibration information. The application adopts an internal speed feedback method, improves the gain margin of external speed feedback, and reduces vibration amplification of the mass damper near the natural frequency, so that the active mass damper vibration reduction effect is improved.

This invention discloses a friction feedforward compensation method and system for a servo system, comprising: identifying segmented friction force model parameters, including maximum static friction torque, Coulomb friction torque, viscous friction coefficient, and critical Stribeck speed, based on speed feedback signals and utilizing the steady-state response of the servo system to simple input signals; modeling the friction torque of the servo system as a piecewise function of speed according to the model parameters, constructing a segmented friction force model to calculate friction force; using the segmented friction force model as a feedforward compensator, calculating the current feedforward amount in each control cycle and superimposing it on the current loop command; calculating the friction compensation amount online according to the real-time speed command and injecting it into the servo system, working together with the original PI feedback control to offset friction disturbances; this invention, through a simplified segmented static model and parameter identification based on steady-state response, greatly reduces the complexity of the algorithm and the difficulty of engineering implementation while ensuring the compensation effect.

The invention belongs to the technical field of motor control, and particularly relates to an ultra-high-speed linear induction motor control method for frequency track self-learning planning. The objective of the invention is to solve the problem of thrust instability caused by insufficient speed measurement precision of an ultra-high-sound linear motor. According to the method, the stable operation area of the linear induction motor is determined by establishing the stable area and the stability margin solving model of the linear induction motor; a thrust and resistance self-learning model of the linear induction motor is constructed by using nonlinear least square optimization, and model parameters are accurately determined; and providing a linear induction motor frequency trajectory planning method based on the self-learning model, and realizing stable speed control of the linear induction motor under an ultra-high-speed working condition. Through simulation verification, the method can enable the actual rotor angular frequency to be gradually close to the given rotor angular frequency, effectively improves the speed control stability of the ultra-high-speed linear motor, does not need to add new hardware equipment, and provides a solution for speed-feedback-free control of the ultra-high-speed linear induction motor.

The application discloses a bearing fault diagnosis method of multistable system random resonance of time-delay feedback control, and belongs to the field of early fault diagnosis of rotary machinery. The method is realized as follows: an original rolling bearing vibration signal is acquired; color noise is added in the rolling bearing vibration signal; an improved signal-to-noise ratio ISNR of the bearing vibration signal is taken as an optimization index, a quantum particle swarm optimization algorithm is adopted to perform combined optimization on system parameters, damping coefficients, time-delay lengths, displacement feedback gain coefficients and speed feedback gain coefficients, and an optimal under-damped multistable system random resonance model of time-delay feedback control containing displacement and speed is obtained; the random resonance model is used to perform random resonance processing on the rolling bearing vibration signal, and the improved signal-to-noise ratio of the bearing vibration signal is improved; and spectrum analysis is performed on the bearing vibration signal output after the random resonance, so that accurate extraction of early weak fault features of the rolling bearing and accurate fault identification in a strong noise background are realized.

The invention discloses a motor control method, device and equipment, and relates to the field of motor driving. Respectively generating a first acceleration signal representing an expected motion state of the system and a second acceleration signal representing an actual vibration state of the system through the speed instruction and the speed feedback signal; the two acceleration signals with different sources and complementary characteristics are combined to generate a current acceleration compensation signal capable of quickly responding to instruction change and stabilizing actual vibration, feed-forward compensation is performed on a speed loop output signal based on the current acceleration compensation signal to obtain an input signal of a current loop, active damping force required by resonance suppression is provided, and the vibration suppression effect is improved. The technical problem that the operation performance of the motion control equipment is reduced and even the equipment is damaged due to resonance is solved, and the technical effects of reducing the flexible resonance of the system, enabling the motion control system to operate more smoothly and improving the durability and the service life of the system are achieved.

The invention discloses a self-adaptive drilling control system and method for a double-wheel slot milling machine. The method comprises the steps that the actual ground pressure and the actual feeding speed of a milling cutter frame during working are obtained; when the actual ground pressure changes, the target feeding speed is adjusted, and a winch flow valve control instruction is generated and used for controlling a winch flow valve; when the actual feeding speed changes, the target ground pressure is adjusted, a winch back pressure valve control instruction is generated and used for controlling a winch back pressure valve, and double-input and double-output closed-loop control is formed. The initial preset values (including the target ground pressure and the target feeding speed) are selected according to different stratums, the target feeding speed can be rapidly adjusted according to the change of the external ground pressure, the ground pressure is fed back and adjusted according to the feeding speed, and automatic return is achieved after overadjustment.

The application relates to a full-electric speed regulating system, a rotating speed sensor is arranged at a steam turbine and used for detecting the rotating speed of the steam turbine; a speed controller is connected with the rotating speed sensor and a servo driver, used for realizing closed-loop control of the rotating speed of the steam turbine and outputting a control instruction to the servo driver; a linear motor linear displacement sensor is connected with the servo driver, used for realizing position and speed feedback of a linear motor moving part; the linear motor moving part is connected with a regulating valve through a lever or direct connection, so that the position of the regulating valve is controlled; and the servo driver is used for realizing closed-loop control of the position and speed of the linear motor moving part. The application uses an electric actuator to replace a traditional hydraulic actuator, the original hydraulic system is omitted, the volume occupied by the speed regulating system is reduced, vibration and noise caused by a hydraulic oil pump, pipelines and other hydraulic systems are reduced, manufacturing difficulty and maintenance requirements are reduced. Meanwhile, the full-electric speed regulating system does not have electro-hydraulic signal conversion, and the control mode is more flexible.

This invention provides a real-time speed control method and system for injection in a die-casting machine. The system includes a human-machine interface, an Ethernet communication interface, an MCU controller, an FPGA high-speed execution unit, a sensor group, and an execution mechanism. The FPGA performs data acquisition, pressure / flow inner loop, amplitude limiting and slope limiting, and parallel drive of valves and pumps. The MCU obtains speed feedback based on the injection plunger position, servo pump speed, and injection chamber pressure change rate according to the outer loop scheduling cycle, and performs stage identification, online parameter identification, candidate model selection, expansion state observer disturbance compensation, and short-time domain model predictive control of the switching window. This method reduces stage switching impact and pressure overshoot by identifying the hydraulic execution channel pilot in the low-speed safety detection interval before injection, performing multi-anchor point curve superposition calibration, stage authorization token interlocking, and multi-source residual fault reconstruction, thereby improving injection accuracy, batch consistency, and operational safety.

The present invention belongs to the technical field related to numerical control technology, and discloses a feedforward method and device for a feed system taking into account system delay, comprising the following steps: (1) inputting a position command signal containing a uniform speed change section and a reverse section to a machine tool; (2) collecting and recording position tracking error data e1 of the uniform speed change section at this time; (3) adjusting a speed feedforward time offset parameter according to the phase difference between a speed feedforward and a speed feedback quantity in a delay link existing in the system, and collecting and recording position tracking error data e2 of the current uniform speed change section; (4) comparing e1 and e2, and determining whether the position tracking error data e2 is close to 0; if so, ending the process and obtaining an optimal speed feedforward time offset parameter that makes the uniform speed tracking error close to 0; otherwise, continuing to adjust the speed feedforward time offset parameter according to the obtained comparison result until the uniform speed tracking error is close to 0. The present invention improves the level of position tracking error control.

The present invention discloses a flexible joint jitter suppression method, system, and storage medium, including the following steps: S1: obtaining the motor end speed as a first speed feedback and a given speed instruction, and the load end speed as a second speed feedback and a given torque feedback; S2: calculating the second speed feedback and the torque feedback through a preset jitter suppression module to obtain a jitter speed; S3: fine-tuning the first speed feedback according to the jitter speed to obtain a jitter speed feedback; S4: the difference between the jitter speed feedback and the speed instruction generates a speed error, which is transmitted to a speed controller, which adjusts the speed error and generates a torque instruction to achieve jitter suppression of the flexible joint. This reduces the fluctuation in the servo motor torque feedback, thereby obtaining a stable speed at the output end of the flexible joint, allowing the robot to accurately and stably position itself during operation.

The invention provides a spherical joint module vibration suppression sliding mode control method based on acceleration feedback, and the method employs an accelerometer to measure the acceleration information of a spherical joint module during trajectory tracking, and feeds the acceleration information back to a sliding mode controller, thereby constructing a novel sliding mode controller. According to the controller, the trajectory tracking performance of the ball joint module is effectively improved, so that the trajectory of the ball joint module can track an expected trajectory within limited time, and the steady-state error of trajectory tracking of the ball joint module is reduced; meanwhile, the acceleration feedback sliding mode controller can effectively reduce the chattering phenomenon in the trajectory tracking process of the ball joint module, closed-loop acceleration feedback enables the ball joint module to achieve real-time vibration suppression under the condition of sudden external interference, and the robust performance of the control system is improved.

The invention discloses a control method and device of an industrial robot, the industrial robot, a storage medium and a computer program product, and the method comprises the steps: designing an observer module, and arranging the observer module at a feedback part of a servo control system; under the condition that the industrial robot runs, observation is carried out through an observer module on the basis of a speed feedback signal of a servo motor and a torque feedback signal of a harmonic speed reducer, and a torque disturbance signal of the industrial robot is obtained; and the torque disturbance signal of the industrial robot is compensated to the torque control of the servo motor on the harmonic speed reducer so as to suppress the tail end vibration of the industrial robot. According to the scheme, the self-adaptive dimensionality reduction state observer is arranged in the feedback part of the servo control system of the industrial robot, the fluctuation torque signal observed by the self-adaptive dimensionality reduction state observer is compensated to the torque control of the servo motor on the harmonic speed reducer, vibration brought by the harmonic speed reducer is restrained, and the control precision of the industrial robot is improved. And dynamic performance of the industrial robot is provided.

The invention relates to a method for controlling at least one actuator (4) comprising a translatably movable piston (4.2) and an electric motor (4.1) for moving the piston (4.2) between a first position set back from a stop and a second position of contact with the stop, the method comprising the step of controlling the power supply to the electric motor (4.1) via speed feedback control of the piston (4.2) by determining, in real time, a current consumed by the electric motor (4.1) in order to detect arrival of the piston (4.2) in the contact position, characterized in that the detection of the contact position comprises the step of determining a slope of change in the current consumed by the electric motor (4.1) as the piston moves and the step of detecting an increase in the slope corresponding to the arrival of the piston (4.2) in the contact position. The invention also relates to a braking device, to a braked wheel and to an aircraft for implementing this method.