CN115167246A

CN115167246A - Wheelchair posture adjusting method and system

Info

Publication number: CN115167246A
Application number: CN202210960386.5A
Authority: CN
Inventors: 王强
Original assignee: National Research Center for Rehabilitation Technical Aids
Current assignee: National Research Center for Rehabilitation Technical Aids
Priority date: 2021-01-07
Filing date: 2021-01-07
Publication date: 2022-10-11
Also published as: CN112859679A; CN112859679B

Abstract

The invention discloses a wheelchair posture adjusting system, which comprises a controller, a sensor circuit, a motor drive and feedback circuit thereof, wherein: the number of the motor drivers and the feedback circuits thereof is 5, and the motor drivers and the feedback circuits thereof are respectively a 1 st motor driver and a feedback circuit thereof, a 2 nd motor driver and a feedback circuit thereof, a 3 rd motor driver and a feedback circuit thereof, a 4 th motor driver and a feedback circuit thereof, and a 5 th motor driver and a feedback circuit thereof; the 5 motor driving and feedback circuits respectively supply power to the five electric push rods; the electric push rod is arranged at the following positions: (1) one backrest is arranged at the position of the backrest and is marked as B1 for adjusting the inclination angle of the backrest; (2) two seats are arranged below the seat and used for controlling ascending and inclining, and the marks are S1 and S2 respectively; (3) two lower leg supports are arranged and marked as L1 and L2 respectively; the controller confirms whether the push rod is in place or not according to the feedback value of the telescopic amount of the electric push rod; the speed of the electric push rod and the movement time of the electric push rod are changed according to different postures.

Description

Wheelchair posture adjusting method and system

The application is a divisional application of an invention patent application with the application number of 202110015283.7, the application date of 2021, 1, 7 and the name of 'a wheelchair posture adjustment system'.

Technical Field

The invention relates to a system for helping old people and patients with motor dysfunction to adjust postures when taking a wheelchair, belongs to the technical field of rehabilitation auxiliary appliances and mobile walking aids, and particularly relates to a wheelchair posture adjusting system.

Background

With the increasing aging degree of the population in China, a plurality of old people lose all or part of the exercise capacity for various reasons every year, and the medical treatment, nursing, living and other aspects of the group become problems which must be faced and solved by the whole society. In order to actually serve the old people and improve the life quality of the old people, the basic solution is to provide a safe, stable, intelligent and portable mobility tool. Aiming at the current situations that the market demand of the huge electric wheelchair in China cannot be effectively met and the high-end intelligent wheelchair product is still monopolized by foreign technologies, the wheelchair posture adjusting system breaks through the key technologies such as the structure of a wheelchair system and the man-machine coordinated motion aiming at the actual demands of the elderly with lower limb dysfunction in different degrees on wheelchair riding comfort and rehabilitation training, and provides the wheelchair posture adjusting system based on the motion intelligent control strategy suitable for the elderly and the software and hardware design of a control system. The adjustment of a plurality of postures such as backrest angle, leg support angle, pedal length, seat surface lifting, seat surface inclination, auxiliary standing (standing), lying and the like can be realized. The wheelchair is beneficial to relieving the most basic requirement problem of the elderly in the aging society on wheelchair traveling safety and comfort.

Disclosure of Invention

In order to realize the purpose of the invention, the following technical scheme is adopted for realizing the purpose:

the utility model provides a motor drive and feedback circuit, includes high-speed optical coupling isolation unit, motor drive unit and low-speed optical coupling isolation unit, wherein: the high-speed optical coupling isolation unit comprises a U2 chip and peripheral circuit elements thereof, the U2 chip is an HCPL2631 chip, a pin 1 of the U2 chip is connected with a port of the processor for outputting PWM1, and a pin 2 is connected with a protection resistor R26; pin 4 is connected with the port of the processor for outputting PWM2, and pin 3 is connected with a protective resistor R30; pin 5 is grounded and connected with a +5V voltage source through a filter capacitor C22; the pin 7 outputs a signal after the optical coupling isolation of the PWM1 and is connected with a +5V voltage source through a pull-up resistor R19, and the pin 6 outputs a signal after the optical coupling isolation of the PWM2 and is connected with the +5V voltage source through a pull-up resistor R20; pin 8 is the power supply terminal of the chip and is connected to a +5V voltage source.

The motor drive and feedback circuit, wherein: the low-speed optical coupling isolation unit comprises a U9 chip, an element UP4 and an element UP2, wherein the U9 chip is a low-speed optical coupling isolation chip PC817, the element UP4 is a voltage comparator MCP6022, and the element U2 is the voltage comparator MCP6022; pin 4 of U9 is connected with pin 1 of UP4, pin 4 of U9 is also connected with a pull-UP resistor R34 and then connected with a +5V voltage source, pin 1 of the U9 chip is connected with SDO, pin 2 is connected with a resistor R38 and then connected with the ground, and pin 3 of U9 is connected with the ground.

The motor drive and feedback circuit, wherein: the resistor R22 is a current sampling resistor, one end of the resistor R is grounded, and the other end of the resistor R is connected with a current sampling point of the bridge rectifier circuit; the current sampling point end of the R22 is also connected with the first end of the resistor R13, and the other end of the R13 is connected with the first end of the resistor R14 and the first end of the capacitor C27; the grounding end of the R22 is also connected with the first end of a resistor R27, the other end of the R27 is connected with the other end of a capacitor C27 and the first end of a resistor R28, the other end of the R28 is connected with the pin 4 of UP2, the pin 3 of UP2 is connected with the other end of the R14, the grounding end of the R22 is also connected with the first end of a resistor R301, and the other end of the R301 is connected with a +1.65V comparison voltage end; the UP2 pin 4 is connected with a first end of a feedback resistor R32, the first end of the R32 is connected with the R28 and the UP2 pin 4, and the other end is connected with the UP2 pin 1 and the UP2 pin 1 to output a current sampling value to the processor; UP2 pin 1 is also connected to a first terminal of resistor R16, and the other terminal of R16 is connected to a first terminal of capacitor C28 and pin 3 of element BAS 70-04; pin 1 of element BAS70-04 is connected to ground and pin 2 is connected to a +3.3V voltage source.

The motor drive and feedback circuit, wherein: pin 4 of the UP4 chip is connected with the other end of the resistor R16, pin 3 is connected with the first end of the resistor R39 and the first end of the resistor R40, the second end of the resistor R39 is connected with a +5V voltage source, and the second end of the resistor R40 is grounded.

The motor drive and feedback circuit, wherein: the high-speed optical coupling isolation unit comprises a high-speed optical coupling isolation chip U2 and peripheral circuit elements thereof, a U2VIN1+ end pin 1 is connected with a port of the processor for outputting PWM1, a VIN 1-end pin 2 is connected with a protection resistor R26, and the resistance value of the R26 is 360 ohms; the VIN2+ end pin 4 is connected with a port of the processor for outputting PWM2, and the VIN 2-end pin 3 is connected with a protective resistor R30; the GND end pin 5 is grounded and is connected with a +5V voltage source through a filter capacitor C22, and the capacitance value of the C22 is 0.1 muF; a VOUT1 pin 7 outputs a signal after optical coupling isolation of PWM1, and is connected with a +5V voltage source through a pull-up resistor R19, and the resistance value of R19 is 510 ohms; a VOUT2 pin 6 outputs a signal after the optical coupling isolation of PWM 2; the VCC end (pin 8) is the power supply end of the chip and is connected with a +5V voltage source.

The motor drive and feedback circuit, wherein: the motor driving unit comprises U6 and U7 chips and peripheral circuit elements thereof, the U6 and U7 chips are motor driving chips, and a VCC end pin 1 of the U6 chip is connected with 12V voltage; the IN end pin 2 is the input end; the COM end pin 4 is grounded, and a filter capacitor C14 is connected between the 12V voltage and the ground; the LO terminal pin 5 is a low-side grid electrode drive output, the HO terminal pin 7 is connected with one end of a 22 ohm resistor R2, the other end of the R2 is connected with a base electrode of an MOS (metal oxide semiconductor) transistor Q4, a collector electrode of the Q4 is connected with a 24V voltage source, and an emitting electrode of the Q4 is connected with a pin 2 of a P3 and a collector electrode of the Q7; the emitter and the collector of Q4 are connected by a diode D7, the base of Q7 is connected with pin 5 of U6 through a 22 ohm resistor R7, and the emitter and the collector of Q7 are connected by a diode D10.

The motor drive and feedback circuit, wherein: u6 chip VS end pin 6 is high-end floating power supply offset voltage end, connects the 2 ends of P3, P31 end and 2 ends connect two power lines of electric putter, P3 is electric putter's drive power end, the VS end still is connected with bootstrap capacitor C7's one end, C7's the other end and VB end pin 8 are connected, VB end pin 8 is connected diode D3's negative pole, D3 is 1N4007, D3's positive pole is connected 12V voltage, the negative pole connects the VB end.

The motor drive and feedback circuit, wherein: the method is characterized in that: a pin 7 at the VB end of the U6 chip is a high-side floating absolute voltage end, a D3 diode 1N4007 is connected between the VB end and 12V voltage, the anode of the D3 is connected with 12V, and the cathode of the D3 is connected with VB; a bootstrap capacitor C7 is connected between VB and VS; the collector and the emitter of Q7 are connected by a diode D10, D10 is 1N4007, the anode of D10 is connected with the emitter of Q7, and the cathode is connected with the collector of Q7.

The motor drive and feedback circuit, wherein: a VCC end pin 1 of the U7 chip is a logic power supply voltage end and is connected with 12V voltage; the IN end pin 2 is the input end; the COM end pin 4 is grounded; a filter capacitor C12 is connected between the voltage of 12V and the ground, an LO terminal pin 5 is a low-side grid electrode driving output, an HO terminal pin 7 is a high-side grid electrode driving output and is connected with one end of a 22 ohm resistor R4, the other end of the R4 is connected with the base electrode of an MOS tube Q2, the collector electrode of the Q2 is connected with a 24V voltage source, and the emitter electrode of the Q2 is connected with the collector electrodes of pins 2 and Q8 of P3; the emitter and the collector of the Q2 are connected by a diode D8, the base of the Q8 is connected with a pin 5 of the U7 through a 22 ohm resistor R8, and the emitter and the collector of the Q8 are connected by a diode D11; the VS terminal pin 6 is connected with the terminal 1 of the P3, the P3 is a driving power supply end of the electric push rod, the VS terminal is also connected with one end of a bootstrap capacitor C8, and the other end of the bootstrap capacitor C7 is connected with a VB terminal pin 8; the VB terminal pin 8 is connected with the cathode of the diode D4; the collector and emitter of Q8 are connected by a diode D11.

The utility model provides a wheelchair attitude adjustment system, includes the treater, sensor circuit, motor drive and its feedback circuit, wherein: the number of the motor drivers and the feedback circuits thereof is 5, and the motor drivers and the feedback circuits thereof comprise a motor driving and feedback circuit 1, a motor driving and feedback circuit 2, a motor driving and feedback circuit 3, a motor driving and feedback circuit 4 and a motor driving and feedback circuit 5; the electric push rod is arranged at the following positions: (1) one backrest is arranged at the position of the backrest and is marked as B1 for adjusting the inclination angle of the backrest; (2) two seats are arranged below the seat and used for controlling ascending and inclining, and the marks are S1 and S2 respectively; (3) two leg supports are arranged below the leg support and are marked as L1 and L2 respectively, wherein the L1 lifts the leg, and the L2 stretches; a motor driver and its feedback circuit as claimed in any one of claims 1-9.

Drawings

FIG. 1 is a block diagram of the control circuit of the intelligent walker;

FIG. 2 is a view showing the position of the electric putter;

FIG. 3 is an equivalent diagram for determining the front-rear tilt angle;

FIG. 4 shows a motor control and protection and sampling circuit;

FIG. 5 is a schematic diagram of the connection between the processor STM32F103RCT6 and the pins of the driving circuit.

Detailed Description

The following detailed description of the present invention will be made with reference to the accompanying drawings 1-5.

A wheelchair attitude adjustment system includes a processor, such as STM32F103RCT6, a lithium battery, a voltage conversion circuit, a bus voltage circuit, a hand controller, a man-machine operation platform, a sensor circuit, a motor drive and a feedback circuit thereof, wherein: the number of the motor drivers and the feedback circuits thereof is 5, and the motor drivers and the feedback circuits thereof comprise a motor driving and feedback circuit 1, a motor driving and feedback circuit 2, a motor driving and feedback circuit 3, a motor driving and feedback circuit 4 and a motor driving and feedback circuit 5.

The lithium battery voltage is generally direct current 24V, and the voltage conversion circuit converts the 24V voltage into 5V and 12V voltage, wherein 5V supplies power for the processor, the sensor circuit and the hand controller, and 12V supplies power for the human-machine operation platform. The bus voltage circuit distributes 24V voltage to the motor driving and feedback circuits which respectively supply power to the five electric push rods.

The five push rods are arranged to adjust the postures, including sitting, standing and lying states, seat ascending and descending, backrest independent adjustment, leg support adjustment and seat inclination adjustment, and the five push rods are used for adjusting various postures.

As shown in fig. 2, the electric push rod is arranged at the following positions:

(1) one backrest is arranged at the position of the backrest and is marked as B1 for adjusting the inclination angle of the backrest;

(2) two seats are arranged below the seat and used for controlling ascending and inclining, and the marks are S1 and S2 respectively;

(3) two leg supports are arranged below the leg support, and are marked as L1 and L2 respectively, wherein the L1 lifts the leg, and the L2 stretches.

The telescopic quantity of the electric push rod defines a feedback value according to the mechanical mechanism, and the controller confirms whether the push rod is in place or not according to the feedback value. The speed of the electric putter and the moving time of the electric putter vary depending on the posture.

(2) The state control of each push rod during the posture adjustment is as follows:

timer 1 (Time 1) of the processor configures frequency prescalers.

The implementation of the electric putter requires a timer to provide the PWM frequency. The PWM frequency determines the execution speed of the electric putter.

(1) Adjusting the backrest: the push rod B1 extends and contracts; the backrest backward leaning action B1 contracts, and the backrest forward leaning action B1 extends; the push rod B1 has long stroke, complex actuating mechanism and large driving current ratio.

A timer 2 (Time 2) of the processor is arranged to provide a PWM control frequency for the backrest adjustment posture of the electric putter B1. The length of the electric push rod B1 is 150mm.

At this time, the PWM control frequency of the electric putter B1 is: 3000Hz;

the start and end points of the position feedback information are: 0 and 150mm;

namely the electric push rod B1 extends and retracts within the range from 0 to 150mm;

setting the contraction parameter of the electric push rod B1 as B1 inversion when the backrest is adjusted to lean backwards;

setting the elongation parameter of the electric push rod B1 as B1 positive rotation when the backrest is adjusted to lean forward;

when the wheelchair backrest is sitting straight, the electric push rod B1 is in an extension state, and the position feedback information at the moment is as follows: 140mm.

When the manual controller is operated to press down a button for adjusting the backrest and push the toggle switch backwards to enable the backrest to lean backwards, the PWM frequency of the electric push rod B1 is 3000Hz, and the state of the electric push rod B1 is that the electric push rod B1 is reversed, namely, is contracted; when the backrest leans backwards to the maximum reclining position of 0mm, the electric push rod B1 stops.

When the hand controller is operated to press down a button for adjusting the backrest and push the toggle switch forward to enable the backrest to lean forward, the PWM frequency of the electric push rod B1 is 3000Hz, and the electric push rod B1 rotates forwards, namely extends; when the backrest leans forward to reach the maximum forward leaning position of 140mm, the electric push rod B1 stops.

(2) Adjusting the leg support: the push rods L1 and L2 extend and contract, the leg stretching action is that L1 and L2 extend simultaneously, L1 lifts the leg, L2 stretches the leg, and L1 and L2 cooperate to complete leg support movement together.

A timer 3 (Time 3) of the processor is configured to provide a PWM frequency for the leg rest adjustment posture of the electric putter L1, and a timer 4 (Time 4) of the processor is configured to provide a PWM frequency for the leg rest adjustment posture of the electric putter L2.

At this time, the PWM control frequency of the electric putter L1 is: 3500Hz, the PWM control frequency of the electric push rod L2 is as follows: 1500Hz;

the starting point and the end point of the position feedback information of the electric push rod L1 are as follows: 0 and 100mm, and the starting point and the end point of the position feedback information of the electric push rod L2 are as follows: 0 and 120mm;

namely, the extension range of the electric push rod L1 is from 0 to 100mm, and the extension range of the electric push rod L2 is from 0 to 120mm;

setting the elongation parameter of an electric push rod L1 as L1 positive rotation and the elongation parameter of an electric push rod L2 as L2 positive rotation when the leg support is adjusted to extend legs forwards;

setting the contraction parameter of an electric push rod L1 as L1 reversal and the contraction parameter of an electric push rod L2 as L2 reversal when the leg support is adjusted to retract the legs backwards;

under the condition that the posture of the backrest of the wheelchair is straight and the leg support is put down (normal sitting posture), the electric push rods L1 and L2 are in an initial state, namely the electric push rods contract to the shortest, and the position feedback information is as follows: the electric push rod L1 is 0, and the electric push rod L2 is 0.

When the manual controller is operated to press down the button of the leg support and push the toggle switch forward to extend the leg support forward, the PWM frequency of the electric push rod L1 is 3500Hz, and the electric push rod is in the state of L1 positive rotation, namely L1 extension; the PWM frequency of the electric push rod L2 is 1500Hz, and the electric push rod is in the state of L2 positive rotation, namely L2 extension. When the leg support is stretched forwards to reach the maximum stretching position, namely L1 reaches 100mm, and L2 reaches 120mm, the electric push rods L1 and L2 stop.

When the manual controller is operated to press down the button of the leg support and push the toggle switch backwards to enable the leg support to retract backwards, the PWM frequency of the electric push rod L1 is 3500Hz, and the state of the electric push rod is L1 reversal, namely L1 retraction; the PWM frequency of the electric push rod L2 is 1500Hz, and the state of the electric push rod is L2 reverse rotation, namely L2 retraction. When the leg support retracts backwards to the minimum retraction position, namely L1 reaches 0 and L2 reaches 0, the electric push rods L1 and L2 stop.

(3) The lying posture is as follows: the push rod B1 is contracted to lower the backrest; l1 and L2 extend simultaneously, L1 lifts legs, and L2 extends legs; the push rods B1, L1 and L2 are matched together to complete lying action; the posture is changed from lying to sitting, and the push rod is reversed.

A timer 2 (Time 2) of the processor is arranged to provide a PWM control frequency for the backrest adjustment posture of the electric putter B1 in the lying posture.

A timer 3 (Time 3) of the processor is configured to provide a PWM frequency for the leg rest adjustment posture of the electric putter L1 in the lying posture, and a timer 4 (Time 4) of the processor is configured to provide a PWM frequency for the leg rest adjustment posture of the electric putter L2 in the lying posture.

At this time, the PWM control frequency of the electric putter B1 is: 2600Hz;

at this time, the PWM control frequency of the electric putter L1 is: 1000Hz, the PWM control frequency of the electric push rod L2 is as follows: 2800Hz;

the starting point and the end point of the position feedback information of the electric push rod B1 are as follows: 0 and 150mm; namely the electric push rod B1 extends and retracts within the range from 0 to 150mm;

setting the contraction parameter of the electric push rod B1 as B1 inversion when the backrest is adjusted to lean backwards in the lying posture;

setting the elongation parameter of the electric push rod B1 as B1 forward rotation when the backrest is adjusted to lean forwards in the lying posture;

setting the elongation parameter of an electric push rod L1 to be L1 positive rotation and the elongation parameter of an electric push rod L2 to be L2 positive rotation when the leg support adjusts to extend legs forwards;

setting the contraction parameter of the electric push rod L1 as L1 inversion and the contraction parameter of the electric push rod L2 as L2 inversion when the leg support is adjusted to retract the legs backwards;

under the condition that the posture of the wheelchair backrest is straight and the leg support is put down (normal sitting posture), the electric push rod B1 is in an extension state, and the position feedback information at the moment is as follows: 0140mm.

The electric push rods L1 and L2 are in an initial state, namely the electric push rods contract to the shortest, and the position feedback information is as follows: the electric push rod L1 is 0, and the electric push rod L2 is 0.

When the manual controller is operated to press down the adjusting lying button and push the toggle switch backwards to enable the wheelchair to lie flat, the PWM frequency of the electric push rod B1 is 2600Hz, and the state of the electric push rod B1 is that B1 is reversed, namely, the electric push rod is contracted; when the backrest leans backwards to the maximum reclining position of 0mm, the electric push rod B1 stops. The PWM frequency of the electric push rod L1 is 1000Hz, and the electric push rod is in a state that the L1 rotates forwards, namely the L1 extends; the PWM frequency of the electric push rod L2 is 2800Hz, and the electric push rod is in the state of L4 positive rotation, namely L2 extension. When the leg support is stretched forwards to reach the maximum stretching position, namely L1 reaches 100mm, and L2 reaches 120mm, the electric push rods L1 and L2 stop.

When the hand controller is operated to press down the lying adjustment button and push the toggle switch forward to adjust the wheelchair from the lying posture to the sitting posture, the PWM frequency of the electric push rod B1 is 2600Hz, and the electric push rod B1 rotates forwards, namely extends; when the backrest is reclined forward to the maximum reclining position 0, the electric push rod B1 is stopped. The PWM frequency of the electric push rod L1 is 1000Hz, and the state of the electric push rod is L1 positive rotation, namely L1 extension; the PWM frequency of the electric plunger L2 is 2800Hz, and the electric plunger is in the state of L2 rotating forward, i.e., L2 extending. When the leg support retracts backwards to the minimum retraction position, namely L1 reaches 0 and L2 reaches 0, the electric push rods L1 and L2 stop.

(4) Overall rising: the push rods S1 and S2 simultaneously extend synchronously to push the seat to ascend and descend. S1 and S2 extend simultaneously, and the seat rises; s1 and S2 contract simultaneously, and the seat descends; the push rods of S1 and S2 are different in model and installation angle, the speed is adjusted through a program, and the expansion and contraction are adjusted according to feedback.

A timer 5 (Time 5) of the processor is configured to provide a PWM frequency for the leg rest adjustment posture of the electric putter S1, and a timer 6 (Time 6) of the processor is configured to provide a PWM frequency for the leg rest adjustment posture of the electric putter S2.

At this time, the PWM control frequency of the electric putter S1 is: 2500Hz, the PWM control frequency of the electric push rod S2 is as follows: 1900Hz;

the starting point and the end point of the position feedback information of the electric push rod S1 are as follows: 0mm and 250mm, and the starting point and the end point of the position feedback information of the electric push rod S2 are as follows: 0 and 200;

namely, the telescopic range of the electric push rod S1 is from 0 to 250mm, and the telescopic range of the electric push rod S2 is from 0 to 200mm;

when the whole is set to ascend, the elongation parameter of the electric push rod S1 is S1 positive rotation, and the elongation parameter of the electric push rod S2 is S2 positive rotation;

when the integral descending is set, the contraction parameter of the electric push rod S1 is S1 reversal, and the contraction parameter of the electric push rod S2 is S2 reversal;

under the condition that the posture of the backrest of the wheelchair is straight and the leg support is put down (normal sitting posture), the electric push rods S1 and S2 are in an initial state, namely the electric push rods contract to the shortest, and the position feedback information is as follows: the electric push rod S1 is 0, and the electric push rod S2 is 0.

When the manual controller is operated to press down the ascending and descending adjusting button and push the switch forwards to lift the seat, the PWM frequency of the electric push rod S1 is 2500Hz, and the state of the electric push rod is S1 positive rotation, namely S1 extension; the PWM frequency of the electric push rod S2 is 1900Hz, and the state of the electric push rod is S2 positive rotation, namely S2 extension. When the seat is lifted to the maximum height position, namely S1 reaches 250mm and S2 reaches 200mm, the electric push rods S1 and S2 are stopped.

When the manual controller is operated to press down the ascending and descending adjustment key and push the toggle switch backwards to enable the seat to descend, the PWM frequency of the electric push rod S1 is 2500Hz, the state of the electric push rod S1 is S1 reverse rotation, namely S1 retracts; the PWM frequency of the electric push rod S2 is 1900Hz, and the state of the electric push rod is S2 reverse rotation, namely S2 retraction. When the seat descends to the minimum height position, namely S1 reaches 0 and S2 reaches 0, the electric push rods S1 and S2 stop.

(5) Integral inclination: the pushers S1 and S2 extend or contract, pushing the seat to tilt. The push rod S1 is close to the front end, the push rod S2 is close to the rear end, the push rod S1 extends, namely inclines backwards, and the push rod S2 extends, namely inclines forwards.

Assuming that the PWM control frequency of the electric putter S1 at this time is: 3500Hz, the PWM control frequency of the electric push rod S2 is as follows: 3500Hz;

the starting point and the end point of the position feedback information of the electric push rod S1 are as follows: 0mm and 250mm, and the starting point and the end point of the position feedback information of the electric push rod S2 are as follows: 0 and 200mm;

when the electric push rod S1 is set to be inclined backwards, the elongation parameter of the electric push rod S1 is S1 positive rotation; when the electric push rod returns from backward tilting, the contraction parameter of the electric push rod S1 is S1 reverse rotation;

when the electric push rod S2 is set to be forwards inclined, the elongation parameter of the electric push rod S2 is S2 forwards rotated; when the electric push rod is returned from forward inclination, the contraction parameter of the electric push rod S2 is S2 reverse rotation;

When the operating hand controller presses the inclination adjusting key to push the toggle switch forwards to enable the seat to incline forwards, the PWM frequency of the electric push rod S2 is 3500Hz, and the electric push rod is in a state of S2 positive rotation, namely S2 extension. When the seat is tilted forward to the maximum forward tilt position, i.e., S2 reaches 00mm, the electric push rod S2 is stopped.

When the operating hand controller presses down the adjusting inclination key and pushes the toggle switch backwards to enable the seat to incline backwards, whether the seat is in a forward inclination state or not is judged firstly, namely whether S2 position feedback information is equal to 0 or not is judged, and if the S2 position feedback information is larger than 0, the seat is judged to be in the forward inclination state and is required to be returned to the original position firstly. The PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 reverse rotation, namely S1 retraction. If the S2 position feedback information is equal to 0, judging that the seat is in the original position, the PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 positive rotation, namely S1 extension; when the seat is tilted backward to the maximum backward tilt position, i.e., S1 reaches 250mm, the electric push rod S1 stops.

(6) Standing posture: all the push rods are matched together to complete standing. The push rods L1 and L2 extend simultaneously, the L1 lifts the leg, the L2 extends the leg, and the L1 and the L2 are matched to jointly complete leg support movement; the push rod B1 is contracted to lower the backrest and enable the backrest of the wheelchair to lie flat; the push rod S1 contracts, the push rod S2 extends, and standing is assisted.

A timer 2 (Time 2) of the processor is arranged to provide a PWM control frequency for the auxiliary standing adjustment posture of the electric putter B1.

The PWM control frequency of the electric push rod B1 when the auxiliary stand is set is: 500Hz;

the start and end points of the position feedback information are: 0 and 150mm;

namely, the telescopic range of the electric push rod B1 is from 0 to 150mm;

setting the back to be upright when the standing adjustment is carried out to stand upwards, and setting the contraction parameter of the electric push rod B1 as B1 to be reversed;

setting the elongation parameter of the electric push rod B1 as B1 positive rotation when the electric push rod B1 is recovered when standing and adjusting to sit downwards;

a timer 3 (Time 3) of the processor is configured to provide a PWM frequency for the standing adjustment posture of the electric putter L1, and a timer 4 (Time 4) of the processor is configured to provide a PWM frequency for the standing adjustment posture of the electric putter L2.

The PWM control frequency of the electric putter L1 when the auxiliary stand is set is: 1500Hz, the PWM control frequency of the electric push rod L2 is as follows: 1200Hz;

when standing adjustment is set, standing is assisted, the leg support extends forwards, the extension parameter of the electric push rod L1 is L1 positive rotation, and the extension parameter of the electric push rod L2 is L2 positive rotation;

when standing adjustment is set, the user sits down in an auxiliary mode, the leg support is retracted backwards, the contraction parameter of the electric push rod L1 is L1 inversion, and the contraction parameter of the electric push rod L2 is L2 inversion;

a timer 5 (Time 5) of the processor is configured to provide PWM frequency for the standing adjustment posture of the electric putter S1, and a timer 6 (Time 6) of the processor is configured to provide PWM frequency for the standing adjustment posture of the electric putter S2.

When the auxiliary standing is set, the PWM control frequency of the electric push rod S1 is as follows: 3500Hz, the PWM control frequency of the electric push rod S2 is as follows: 2500Hz;

the starting point and the end point of the position feedback information of the electric push rod S1 are as follows: 0mm and 250mm, and the starting point and the end point of the position feedback information of the electric push rod S2 are as follows: 0 and 200mm; when the wheelchair is assisted to stand, the wheelchair seat firstly ascends, and when the wheelchair seat ascends to a set position, the ascending is stopped, and at the moment, the position feedback information of the electric push rod S1 is 120mm, and the position feedback information of the electric push rod S2 is 120mm, and then S2 independently works.

When the auxiliary standing is set, the wheelchair seat ascends firstly, the elongation parameter of the electric push rod S1 is S1 positive rotation, and the elongation parameter of the electric push rod S2 is S2 positive rotation; when the push rod position feedback information of S1 reaches 120mm, the seat is tilted forwards again, S2 continues to extend, and the parameter is still S2 positive rotation until the distance reaches 200mm; after the auxiliary stand is in a set position, when the auxiliary seat is taken down (after the stand is in a sitting position, the auxiliary seat is returned to the sitting position again), the contraction parameter of the electric push rod S2 is S2 reverse rotation when the electric push rod is inclined forwards and returned; when the distance reaches 120mm, the electric push rods S1 and S2 work simultaneously, the retraction parameter of the electric push rod S1 is S1 reversal, and the retraction parameter of the electric push rod S2 is S2 reversal;

the whole process of auxiliary standing is as follows:

when the hand controller is operated to press the auxiliary standing key and push the switch forwards to enable the wheelchair to stand, whether the seat is in a sitting posture in-situ state or not is judged firstly.

If the seat is judged to be in the early stage of the non-standing state or the standing state, the electric push rods S1 and S2 extend, namely the parameters S1 rotate forwards and S2 rotate forwards; the electric push rod B1 extends, namely the parameter is B1 positive rotation; the electric push rods L1 and L2 extend, namely parameters of L1 forward rotation and L1 reverse rotation are adopted. When the position feedback information of the electric push rod S1 reaches 120mm and the position feedback information of the electric push rod S2 reaches 120mm, the electric push rod S1 stops, the electric push rods S2, B1, L1 and L2 continue to execute according to the original state parameters until the push rods reach the set end point.

And finishing the auxiliary standing.

If the position feedback information of the S2 is larger than 120mm and smaller than 250mm, judging that the seat is in the later stage of the standing state, stopping the electric push rod S1, and continuously extending the electric push rod S2, namely positively rotating the parameter S2; the electric push rod B1 extends, namely the parameter is B1 positive rotation; the electric push rods L1 and L2 extend, namely parameters of L1 forward rotation and L1 reverse rotation are adopted. When the position feedback information of the electric push rod S1 reaches 120mm and the position feedback information of the electric push rod S2 reaches 120mm, the electric push rod S1 stops, the electric push rods S2, B1, L1 and L2 continue to execute according to the original state parameters until the push rods reach the set end point.

From the standing position back to the sitting position, the process is performed in reverse as previously described.

The concrete mode of judging the slope of the seat system and adapting to the road condition change is as follows:

further, for safety, if the sensor module of the wheelchair detects that the walker has an angular change in three directions X, Y, Z, the sensor module comprises a gyroscope and a signal acquisition unit, as shown in fig. 3, the walker is determined to be in danger of toppling. The signal acquisition unit converts the angle into an analog voltage signal through a gyroscope and outputs the analog voltage signal, the main controller acquires the analog voltage signals output in two directions of X, Y and Z of the signal acquisition unit, converts the analog voltage signals into digital signals Ax, ay and Az representing acceleration, judges whether the forward tilting and the backward tilting need signals output in two directions of X, Z, and an equivalent diagram is shown in figure 3,

the tilt angle in the front-rear (X) direction is calculated according to the following formula,

the inclination angle in the X direction is the inclination angle A of the X axis of the gyroscope and the X axis of the horizontal plane:

α＝arctan ^-1 (Ax/Az)

judging whether the automobile is inclined forwards or backwards, and if Ax is larger than 0, alpha is larger than 0 and the automobile is inclined forwards; when Ax is less than 0, alpha is less than 0 and inclines backwards.

The first threshold value of the inclination angle is not more than 8 °, the second threshold value is not more than 12 °, and the third threshold value is not more than 20 °.

(1) Seat inclination when α is less than or equal to 8 ° in absolute value:

the pushers S1 and S2 extend or contract to push the inclination of the seat. The push rod S1 is close to the front end, the push rod S2 is close to the rear end, the push rod S1 extends, namely inclines backwards, and the push rod S2 extends, namely inclines forwards.

A timer 5 (Time 5) is set to provide a PWM frequency for the leg rest adjustment posture of the electric putter S1, and a timer 6 (Time 6) is set to provide a PWM frequency for the leg rest adjustment posture of the electric putter S2.

At this time, the PWM control frequency of the electric putter S1 is: 3500Hz, the PWM control frequency of the electric push rod S2 is as follows: 3500Hz;

the starting point and the end point of the position feedback information of the electric push rod S1 are as follows: 0 and 120 × sin8 ° mm; and 120 multiplied by sin 8-degree mm is position feedback information of the electric push rod S1 inclining by 8 degrees. The starting point and the end point of the position feedback information of the electric push rod S2 are as follows: 0 and 120 × sin8 ° mm; and 120 multiplied by sin 8-degree mm is position feedback information of the electric push rod S2 inclining by 8 degrees.

Namely, the telescopic range of the electric push rod S1 is from 0 to 120 multiplied by sin8 degrees mm, and the telescopic range of the electric push rod S2 is from 0 to 120 multiplied by sin8 degrees mm;

when the electric push rod S1 is set to be inclined backwards, the elongation parameter of the electric push rod S1 is S1 positive rotation; when the electric push rod is returned from backward inclination, the contraction parameter of the electric push rod S1 is S1 reverse rotation;

When α > 0, the seat is tilted forward, and it is first determined whether the seat is in a tilted state, i.e., whether the S1 position feedback information is equal to 0, and whether the S2 position feedback information is equal to 0. If the S1 position feedback information is larger than 0, or if the S2 position feedback information is larger than 0, the seat is judged to be in the inclined state, and the seat needs to be returned to the original position firstly. The PWM frequency of the electric push rod S2 is 3500Hz, and the state of the electric push rod is S2 positive rotation, namely S2 extension. When the seat is tilted forward to a forward tilt 8 degree position, i.e., S2 reaches 120 × sin8 ° mm, the electric push rod S2 stops.

When alpha is less than 0 degree, the seat tilts backwards, whether the seat is in a tilting state is judged, namely whether the S1 position feedback information is equal to 0 or not is judged, and whether the S2 position feedback information is equal to 0 or not is judged. If the S1 position feedback information is greater than 0 or if the S2 position feedback information is greater than 0, it is determined that the seat is in the tilted state, and the seat is first returned to the home position. The PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 reverse rotation, namely S1 retraction. If the S2 position feedback information is equal to 0, judging that the seat is in the original position, the PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 positive rotation, namely S1 extension; when the seat is tilted backward to a backward tilt 8 degree position, that is, S1 reaches 120 × sin8 ° mm, the electric push rod S1 stops.

(2) Seat inclination when 8 ° < α absolute value < 12 °:

the starting point and the end point of the position feedback information of the electric push rod S1 are as follows: 0 and 120 × sin12 °;120 × sin12 ° is position feedback information of the electric putter S1 inclined by 12 °. The starting point and the end point of the position feedback information of the electric push rod S2 are as follows: 0 and 120 × sin12 °; s2_ QS _ F2_12 is position feedback information of the electric putter S2 tilted by 12 °.

Namely, the expansion range of the electric push rod S1 is from 0 to 120 multiplied by sin12 degrees, and the expansion range of the electric push rod S2 is from 0 to 120 multiplied by sin12 degrees;

when the electric push rod S2 is set to be forwards inclined, the elongation parameter of the electric push rod S2 is S2 forwards rotated; when the electric push rod S2 is returned from forward inclination, the contraction parameter of the electric push rod S2 is S2 reverse rotation;

When α > 0, the seat is tilted forward, and it is first determined whether the seat is in a tilted state, i.e., whether the S1 position feedback information is equal to 0, and whether the S2 position feedback information is equal to 0. If the S1 position feedback information is greater than 0 or if the S2 position feedback information is greater than 0, it is determined that the seat is in the tilted state, and the seat is first returned to the home position. The PWM frequency of the electric push rod S2 is 3500Hz, and the state of the electric push rod is S2 positive rotation, namely S2 extension. When the seat is tilted forward to a forward tilt angle of 12 degrees, i.e., S2 reaches 120 × sin12 °, the electric push rod S2 is stopped.

When alpha is less than 0, the seat tilts backwards, whether the seat is in a tilting state is judged, namely whether the S1 position feedback information is equal to 0 is judged, and whether the S2 position feedback information is equal to 0 is judged. If the S1 position feedback information is larger than 0, or if the S2 position feedback information is larger than 0, the seat is judged to be in the inclined state, and the seat needs to be returned to the original position firstly. The PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 reversal, namely S1 retraction. If the S2 position feedback information is equal to 0, judging that the seat is in the original position, the PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 positive rotation, namely S1 extension; when the seat is tilted backward to a backward tilt 12 degree position, that is, S1 reaches 120 × sin12 °, the electric push rod S1 stops.

(3) Seat tilt when 12 ° < α absolute < 20 °:

the starting point and the end point of the position feedback information of the electric push rod S1 are as follows: o and 120 × sin20 °;120 × sin20 ° is position feedback information of the electric putter S1 inclined by 20 °. The starting point and the end point of the position feedback information of the electric push rod S2 are as follows: 0 and 120 × sin20 °;120 × sin20 ° is position feedback information of the electric putter S2 inclined by 20 °.

Namely, the extension range of the electric push rod S1 is from 0 to 120 multiplied by sin20 degrees, and the extension range of the electric push rod S2 is from 0 to 120 multiplied by sin20 degrees;

When α > 0, the seat is tilted forward, and it is first determined whether the seat is in a tilted state, i.e., whether the S1 position feedback information is equal to 0, and whether the S2 position feedback information is equal to 0. If the S1 position feedback information is greater than 0 or if the S2 position feedback information is greater than 0, it is determined that the seat is in the tilted state, and the seat is first returned to the home position. The PWM frequency of the electric push rod S2 is 3500Hz, and the state of the electric push rod is S2 positive rotation, namely S2 extension. When the seat is tilted forward to reach the forward tilt 20 degree position, i.e., S2 reaches 120 × sin20 °, the electric push rod S2 stops.

When alpha is less than 0, the seat tilts backwards, whether the seat is in a tilting state is judged, namely whether the S1 position feedback information is equal to 0 is judged, and whether the S2 position feedback information is equal to 0 is judged. If the S1 position feedback information is larger than 0, or if the S2 position feedback information is larger than 0, the seat is judged to be in the inclined state, and the seat needs to be returned to the original position firstly. The PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 reverse rotation, namely S1 retraction. If the S2 position feedback information is equal to 0, judging that the seat is in the original position, the PWM frequency of the electric push rod S1 is 3500Hz, and the state of the electric push rod is S1 positive rotation, namely S1 extension; when the seat is tilted backward to reach a backward tilt 20 degree position, i.e., S1 reaches 120 × sin20 °, the electric push rod S1 stops.

(4) When the absolute value of alpha is more than or equal to 20 degrees, the wheelchair is forbidden, and the seat is forbidden to incline:

(5) When the wheelchair drives off the ramp, the wheelchair seat is restored, the electric push rods S1 and S2 return to the initial state, and the position feedback information is as follows: the electric push rod S1 is 0 and the electric push rod S2 is 0.

As shown in fig. 4, the circuit is a motor driving and feedback circuit of one of 5 motor driving and feedback circuits, and the other four circuits are the same as the motor driving and feedback circuit, and the circuit structure is specifically described as follows, where the motor driving and feedback circuit includes a high-speed optical coupling isolation unit, a motor driving unit, and a low-speed optical coupling isolation unit, where:

the high-speed optical coupling isolation unit comprises a U2 chip HCPL2631 and peripheral circuit elements thereof, the HCPL2631 is a high-speed optical coupling isolation chip and is used for isolating a digital device and a power device, PWM signals sent by the processor are changed into more effective motor driving PWM signals, and meanwhile, the processor is prevented from being damaged by large induction voltage generated by the motor.

A VIN1+ end (pin 1) of the chip HCPL2631 is connected with a port of the processor for outputting PWM1, a VIN 1-end (pin 2) is connected with a protective resistor R26, and the resistance value of the R26 is 360 ohms; the VIN2+ end (pin 4) is connected with the port of the processor for outputting PWM2, the VIN 2-end (pin 3) is connected with a protective resistor R30, and the resistance value of the R30 is 360 ohms; the GND end (pin 5) is grounded and is connected with a +5V voltage source through a filter capacitor C22, and the capacitance value of the C22 is 0.1 muF; the VOUT1 (pin 7) outputs a PWM1 optical coupler isolated signal which is PWM1_ IN, and is connected with a +5V voltage source through a pull-up resistor R19, the resistance value of R19 is 510 ohms, and the R19 is used for protecting a chip, so that the voltage of the PWM1_ IN is within the working range of the chip HCPL 2631; the VOUT2 (pin 6) outputs a PWM2 optical coupling isolation signal which is PWM2_ IN, and is connected with a +5V voltage source through a pull-up resistor R20, the resistance value of R20 is 510 ohms, and the R20 is used for protecting a chip, so that the voltage of the PWM2_ IN is within the working range of the chip HCPL 2631; the VCC end (pin 8) is the power supply end of the chip and is connected with a +5V voltage source.

The motor driving unit comprises U6 and U7 chips and peripheral circuit elements thereof, the U6 and U7 chips are IR2104S, the motor driving unit is a dual-channel, grid-driven, high-voltage and high-speed power motor driving chip, and a bridge rectifier circuit is adopted for controlling the motor.

The U6 chip is IR2104S, a dual channel, gate driven, high speed power motor driver chip. VCC end (pin 1) is logic power voltage end, which is connected with 12V voltage; the IN end (pin 2) is an input end, the PWM1_ IN signal is a PWM1 signal output by the processor, and the signal after being isolated by the HCPL2631 chip is used as the input of U6; the COM terminal (pin 4) is a ground potential terminal of the logic circuit and is grounded. A filter capacitor C14 is connected between the 12V voltage and the ground, and the capacitance value of the C14 is 0.1 muF; the LO terminal (pin 5) is a low-side gate drive output, the HO terminal (pin 7) is a high-side gate drive output, one end of a 22 ohm resistor R2 is connected, the other end of the R2 is connected with the base electrode of an MOS tube Q4, the N-channel field effect tubes Q4 and Q7 are optional, the model is IR540N, the collector electrodes of the N-channel field effect tubes Q4 and Q7 are connected with a 24V voltage source, and the emitter electrodes of the Q4 are connected with the collector electrodes of the pins 2 and Q7 of the P3. The emitter and the collector of Q4 are connected by a diode D7, and D7 is 1N4007, thereby preventing the circuit current from flowing backward. The base of Q7 is connected to pin 5 of U6 through a 22 ohm resistor R7, the emitter and collector of Q7 are connected by a diode D10, D10 is 1N4007, and circuit current backflow is prevented.

The VS end (pin 6) is a high-end floating power supply offset voltage end, is connected with the 2 end of the P3 (the P3 is a power supply positive and negative interface of the electric push rod, the 1 end and the 2 end are connected with two power lines of the electric push rod), the P3 is a driving power supply end of the electric push rod, the VS end is also connected with one end of a bootstrap capacitor C7, the other end of the C7 is connected with the VB end (pin 8), and the capacitance value of the C7 is 1.5 muF. During the turn-on period of Q7, the potential of the VS terminal is pulled down to the ground, and a floating power supply is formed between VB and VS by charging the bootstrap capacitor C7. The presence of bootstrap capacitor C7 causes the collector of MOS transistor Q7 to form a power supply. And a VB terminal (pin 8) is a high-side floating absolute voltage terminal and is connected with the cathode of a diode D3, the D3 is 1N4007, the anode of the D3 is connected with 12V voltage, and the cathode is connected with the VB terminal.

The VB terminal (pin 7) is a high-side floating absolute voltage terminal, a D3 diode 1N4007 is connected between the VB terminal and the 12V voltage, the anode of the D3 diode is connected with 12V, and the cathode of the D3 diode is connected with VB. And a bootstrap capacitor C7 is connected between VB and VS, and the capacitance value of C7 is 1.5 muF.

The collector and the emitter of Q7 are connected by a diode D10, D10 is 1N4007, the anode of D10 is connected with the emitter of Q7, and the cathode is connected with the collector of Q7.

The U7 chip is IR2104S, a dual channel, gate driven, high speed power motor driver chip. The VCC end (pin 1) is a logic power supply voltage end and is connected with 12V voltage; the IN end (pin 2) is an input end, the PWM2_ IN signal is a PWM2 signal output by the processor, and the signal is isolated by the HCPL2631 chip and is used as the input of U7; the COM terminal (pin 4) is a logic circuit ground potential terminal and is grounded. A filter capacitor C12 is connected between the 12V voltage and the ground, and the capacitance value of the C12 is 0.1 muF; the LO terminal (pin 5) is a low-side gate drive output, the HO terminal (pin 7) is a high-side gate drive output, one end of a 22 ohm resistor R4 is connected, the other end of the R4 is connected with the base of an MOS tube Q2, N-channel field effect tubes Q2 and Q8 are IR540N, the collectors of the Q2 are connected with a 24V voltage source, and the emitters of the Q2 are connected with the collectors of pins 2 and Q8 of P3. The emitter and collector of Q2 are connected by a diode D8, D8 being 1N4007, preventing circuit current from flowing back. The base of Q8 is connected to pin 5 of U7 through a 22 ohm resistor R8, the emitter and collector of Q8 are connected by a diode D11, D11 is 1N4007, and circuit current backflow is prevented. The output end of the 24V voltage source is connected with the anode of the electrolytic capacitor C2, the cathode of the C2 is grounded, and the C2 provides filtering for the 24V voltage source.

The VS end (pin 6) is a high-end floating power offset voltage end and is connected with the end 1 of the P3, the P3 is a driving power supply end of the electric push rod, the VS end is also connected with one end of a bootstrap capacitor C8, the other end of the C7 is connected with the VB end (pin 8), and the capacitance value of the C8 is 1.5 muF. During the turn-on period of Q8, the potential of the VS terminal is pulled down to the ground, and a floating power supply is formed between VB and VS by charging the bootstrap capacitor C8. The collector of the MOS transistor Q8 forms a power supply by the existence of the bootstrap capacitor C8. The VB terminal (pin 8) is a high-side floating absolute voltage terminal and is connected with the cathode of a diode D4, the D4 is 1N4007, the anode of the D4 is connected with 12V voltage, and the cathode is connected with the VB terminal.

The VB terminal (pin 7) is a high-side floating absolute voltage terminal, a D4 diode 1N4007 is connected between the VB terminal and the 12V voltage, the anode of the D4 diode is connected with 12V, and the cathode of the D4 diode is connected with VB. And a bootstrap capacitor C8 is connected between VB and VS, and the capacitance value of C8 is 1.5 muF.

The collector and emitter of Q8 are connected by diode D11, D11 is 1N4007, the anode of D11 is connected with the emitter of Q8, and the cathode is connected with the collector of Q8.

The driving circuit configured by the chips U6 and U7 is described as follows: c7 and D3 are a bootstrap capacitor and a diode, respectively (C8 and D4 of the chip U7 are a bootstrap capacitor and a diode, respectively, for the same reason). Assume that during Q4 off, C7 has been charged to a sufficient voltage (Vc 7 ≈ Vcc). Then, with SD high, HO is on, LO is off, vc7 is added between the gate and emitter of Q4, and C7 is discharged through HO, R2 and Q4 gate capacitance Cq1, thereby charging Cq 1. At this time, vc7 can be equivalent to a voltage source. And when the HIN is at a low level, the LO is switched on, the HO is switched off, and the gate charge of the Q4 is rapidly released, so that the Q4 is switched off. Then after a short dead time (td), LIN is high, Q7 is on, VCC charges C4 via D3, Q7 and rapidly supplements C4, and the cycle repeats.

When HO high level, LO low level of chip U6, make Q4 switch on, Q7 cuts off, simultaneously, HO low level, LO high level of chip U7, Q2 cuts off, Q8 switches on, +24V mains voltage's positive pole is connected to binding post P3's 2 pins, binding post P3's 1 pin ground connection, the motor positive pole is 2 pins, the negative pole is 1 pin, the electric current flows through electric putter from +24V through binding post P3's 2 pins inside and comes out from binding post P3's 1 pin, through sampling resistance R22, gets into the earthing terminal. At this time, the electric push rod is defined as forward rotation.

When the HO low level and the LO high level of the chip U6, Q4 is turned off and Q7 is turned on, meanwhile, the HO high level and the LO low level of the chip U7 are that Q2 is turned on and Q8 is turned off, the positive pole of the +24V power voltage is connected to the 1 pin of the connecting terminal P3, the 2 pin of the connecting terminal P3 is grounded, the positive pole of the motor is the 1 pin, the negative pole of the motor is the 2 pin, the current flows through the electric push rod from +24V through the 1 pin of the connecting terminal P3, flows out from the 2 pin of the connecting terminal P3, passes through the sampling resistor R22 and enters the ground terminal. The electric push rod is defined as reverse rotation.

The diodes D7, D8, D10, D11 function to prevent current from flowing backwards, causing a short circuit between the +24V supply and ground.

The low-speed optical coupling isolation unit comprises a U9 chip and peripheral circuit elements thereof, the U9 chip is a low-speed optical coupling isolation chip PC817, and the low-speed optical coupling isolation unit is used for isolating a digital device from a power device and avoiding high voltage from damaging a processor and the power chip. The main functions are as follows: (1) An enabling signal SD0 signal sent by the isolation processor is used for preventing the SD0 signal voltage from being too high to damage the processor, and an SDO signal is used as an enabling end of the U6 and U7 chips to control the chips to work; (2) The SD signal (the SD signal is referred to as an SD signal after the SDO signal is isolated by the U9 chip) is controlled to be low, the function of enabling the operation of the chip IR2104S is disabled, and the chip IR2104S is protected. The element UP4 is the voltage comparator MCP6022, when the voltage at the "+" input terminal is higher than the "-" input terminal, the output of the voltage comparator MCP6022 is at high level, when an excessive voltage signal is input at the "-" input terminal (pin 4) of the voltage comparator MCP6022 and is higher than the comparison value at the "+" input terminal (pin 3), the output of the comparator (pin 1) is at low level, the SD terminals (U6 and U7, pin 3) of the IR2104S are connected together) receive low level, and the IR2104S chip is disabled. The SD end (pin 4) of U9 is connected with pin 1 of UP4, the SD end (pin 4) of U9 is also connected with a pull-UP resistor R34 and then connected with a +5V voltage source, the resistance value of R34 is 360 ohms so as to prevent the SD voltage from being overhigh, the maximum voltage is forcibly set to be +5V, the processor is protected, pin 1 of the U9 chip is connected with SDO, pin 2 is connected with a resistor R38 and then grounded, the resistance value of R38 is 360 ohms, and pin 3 is grounded.

R22 is a current sampling resistor, a precision alloy resistor with the resistance value of 0.002 ohm and 5W, one end of the current of the electric push rod is grounded through R22 and R22, and the other end is connected with a current sampling point of the bridge rectifier circuit. The current sampling point end of the resistor R22 is also connected with the first end of the resistor R13, the resistance value of the resistor R13 is 1K ohm, the other end of the resistor R13 is connected with the first end of the resistor R14 and the first end of the capacitor C27, the resistance value of the resistor R14 is 1K ohm, and the capacitance value of the capacitor C27 is 68pF. The grounding end of the resistor R22 is also connected with the first end of the resistor R27, the resistance value of the R27 is 1K ohm, the other end of the R27 is connected with the other end of the capacitor C27 and the first end of the resistor R28, the resistance value of the R28 is 1K ohm, the other end of the R28 is connected with the '-' input end (pin 4) of the UP2 comparator MCP6022, the '+' input end (pin 3) of the MCP6022 is connected with the other end of the R14, the first end of the resistor R301 is also connected, the resistance value of the R301 is 1K ohm, and the other end of the R301 is connected with the +1.65V comparison voltage end. An input end (pin 4) of the MCP6022 is connected with a first end of a feedback resistor R32, the resistance value of the R32 is 24K ohms, the first end of the R32 is connected with the R28 and an input end (pin 4) of the MCP6022, the other end of the R32 is connected with an output end (pin 1) of the MCP6022, an output end (pin 1) of the MCP6022 outputs a current sampling value to a DC _ I end of the processor, and the processor can learn whether the dot push rod works and whether the working state is normal or not through analysis of the current sampling value.

The output end (pin 1) of the UP2 chip MCP6022 is also connected with the first end of a resistor R16, the resistance value of the R16 is 1K ohm, the other end of the R16 is connected with the first end of a capacitor C28 and a pin 3 of a transient diode element BAS70-04, the element BAS70-04 has the function of limiting the voltage of the output end (pin 1) of the MCP6022 to be less than +3.3V, and when the voltage of the output end (pin 1) of the MCP6022 is overlarge, the element BAS70-04 clamps the voltage +3.3V, so that the processor current sampling port is prevented from being damaged due to overhigh voltage. Pin 1 of element BAS70-04 is connected to ground and pin 2 is connected to a +3.3V voltage source.

Pin 4 of the UP4 chip is connected with the other end of the resistor R16, pin 3 is connected with a first end of a 10K ohm resistor R39 and a first end of a 5.4K ohm resistor R40, a second end of the resistor R39 is connected with a +5V voltage source, and a second end of the resistor R40 is grounded.

In order to protect the electric push rod, the maximum current is set to be 8A, and the current sampling current limiting value is 8A; the voltage drop generated on the alloy resistor R22 is 8A multiplied by 0.002R =0.016V, the UP2 comparator MCP6022 and the peripheral circuit thereof have the function of amplifying 0.016V by 12+1 times, and the specific calculation formula is as follows: u = U ₀ ×[1+R24/(R27+R28)]=0.0016V × 13=0.208v; when the comparison voltage is added to 1.65V, the output is 1.65V +0.208V =1.858V, and the UP4 comparator MCP6022 is used for comparing the voltages at the + input end and the-input end. The comparative voltage is 1.858V. The resistance of R39 is set to 10K ohms, from which a resistance of R40 of approximately 5.4K ohms is calculated.

When the voltage at the "+" input terminal is higher than the voltage at the "-" input terminal, the output of the voltage comparator is at high level, when an excessive voltage signal is input at the "-" input terminal (pin 4) of the comparator MCP6022 and is greater than the comparison value at the "+" input terminal (pin 3), the output of the comparator (pin 1) is at low level, the SD terminal of the IR2104S receives low level, and the IR2104S chip is disabled. The SD end of the U9 is also provided with a pull-up resistor R34, and the resistance value of the R34 is 360 ohms so as to prevent the SD voltage from being overhigh, and the maximum voltage is forcibly set to be +5V to protect the processor.

The terminal P5 is connected with a position feedback signal end of the electric push rod. The feedback resistor (not shown in the figure, the feedback resistor is arranged inside the electric push rod and used for calibrating the position information feedback signal, namely, the analog signal is output to represent the stretching position of the electric push rod, and the analog signal is converted into the voltage signal which can be identified by the processor through the P5 peripheral circuit) so as to calibrate the position feedback information of the electric push rod, namely, the analog signal is output to represent the stretching position of the electric push rod, and the P5 peripheral circuit converts the analog signal into the voltage signal which can be identified by the processor. Pin 1 of P5 is connected with +3.3V voltage source and connected with first end of filter capacitor C20, the capacitance value of C20 is 0.1 muF, and second end of filter capacitor C20 is grounded. Pin 2 is connected with a first end of a resistor R20, the resistance value of the resistor R20 is 120 ohms, and the other end of the resistor R20 is connected with DC _ P. And the DC _ P is an analog value signal output node of a position feedback sampling resistor built in the electric push rod, and the specific position of the electric push rod can be calculated according to the DC _ P value. The DC _ P is connected with a position feedback information sampling end of the processor, the other end of the R20 is also connected with a first end of the C24, the C24 is a filter capacitor and keeps the stability of the position feedback information sampling received by the processor, the capacitance value of the C24 is 0.1 muF, a second end of the C24 is grounded, and the pin 3 of the P5 is grounded.

The following beneficial effects can be obtained by the circuit of the invention: 1. the input impedance of the sampling circuit is close to infinity, the output resistance is 0, the motor driving circuit is protected, and the sampling efficiency is improved. 2. The comparison voltage of 1.65V is introduced, so that the calculation value of the UP2 amplifier MCP6022 is corrected, and the sampling precision of the current is improved. 3. Transient diode BAS70-04 effectively protects the analog input IO pin of the processor chip and avoids damage to the IO pin due to unpredictable high voltage. 4. The MCP6022 of the UP4 forms a comparator which can drive the enabling ends of the U6 and U7 chips in real time, so that the IR2104S chip and the processor are protected, and damage to a motor and a control system caused by overcurrent is avoided.

Claims

1. The utility model provides a wheelchair attitude adjustment system, includes controller, sensor circuit, motor drive and feedback circuit, its characterized in that:

the number of the motor drivers and the feedback circuits thereof is 5, and the motor drivers and the feedback circuits thereof are respectively a 1 st motor driver and a feedback circuit thereof, a 2 nd motor driver and a feedback circuit thereof, a 3 rd motor driver and a feedback circuit thereof, a 4 th motor driver and a feedback circuit thereof, and a 5 th motor driver and a feedback circuit thereof; the 5 motor driving and feedback circuits respectively supply power to the five electric push rods;

the electric push rod is arranged at the following positions: (1) one backrest is arranged at the position of the backrest and is marked as B1 for adjusting the inclination angle of the backrest; (2) two seats are arranged below the seat and used for controlling ascending and inclining, and the marks are S1 and S2 respectively; (3) two leg supports are arranged below the leg support and marked as L1 and L2 respectively;

the controller confirms whether the push rod is in place or not according to the feedback value of the telescopic amount of the electric push rod; the speed of the electric putter and the moving time of the electric putter vary depending on the posture.