RU220273U1 - Board for controlling a bionic prosthesis - Google Patents

Abstract

The utility model relates to the field of bioprosthetics. The device is designed for connection to a bionic prosthetic human hand and installation inside its body. The device is a printed circuit board with electronic components installed on it. Structurally, the device consists of 3 blocks: a bionic control unit. prosthesis, power control unit and current sensor unit. The board performs bionic control functions. prosthesis and battery control. The prosthetic control functions include reading and processing signals from myographic sensors installed on the preserved part of the arm, as well as controlling the motors that drive the bionic. prosthesis. Battery monitoring features include overheat protection and deep discharge protection.

Description

Field of technology

The utility model relates to the field of medical technology, namely bioprosthetics; in particular, the device is designed to be connected to a bionic prosthetic human arm and installed inside its body. It is also possible to use a utility model in the field of teaching technical and biomedical sciences as a management system for educational stands and layouts.

State of the art

Currently, from the prior art, there are numerous descriptions of bionic prostheses in general, but a small number of descriptions of the control system of bionic prostheses, as a separate device, performing the tasks of controlling a bionic prosthesis. It is known that there is a module for registration and primary processing of biopotentials (RU 204901 U1, 06/17/2021), which can be used in control systems for bionic limbs. This device is distinguished by the fact that it provides registration, primary processing and amplification of signals from EMG or EEG sensors and can be connected to an external microcontroller, and is also equipped with a common-mode signal inversion unit as a means of suppressing common-mode interference and an input signal buffering unit in the form of two buffers , connected by the inputs to the mentioned contact elements, and by the outputs to the corresponding inputs of the instrumentation amplifier and the input of the common mode noise signal inversion block, while the output of the inversion block is connected to the contact element inserted into the device to provide feedback, ensuring the closure of the inverted common mode noise signal from the outputs buffers to the user's body, the ADC output and the digital potentiometer data bus are connected by a common SPI data bus. The disadvantage of the analogue is the lack of a microcontroller for final processing and analysis of the signal from the sensors and calculation of the control of the electric motors of the bionic prosthesis.

There is also an analogue described in patent RU 2635632 C1, November 14, 2017, in which the EMG signal is processed; transferring a set of EMG signal features to the control system of an intelligent bionic limb; determining the type of gesture based on a set of features of the EMG signal through the use of an artificial neural network; generation of a control signal based on a certain type of gesture and transmission to the motors that drive the fingers of the bionic limb. This analogue provides a simple signal amplification circuit using an instrumentation amplifier and a "right-foot driver" (common-mode signal inversion) with a fixed gain. The disadvantage of the analogue is that the control system for an intelligent bionic limb consists of numerous blocks interconnected by flexible cables and located at a distance from each other in different parts of the bionic limb, which reduces the reliability of the system and the noise immunity of the signal transmission line, and also increases the overall size of the system management.

The closest prototype is the prosthesis control system, described as part of a bionic hand prosthesis in patent RU 176303 U1, 01/16/2018. The prosthesis control system is made in the form of a microprocessor system and includes a prosthesis control microcontroller and connected to it control drivers of electric drives of five-finger flexion systems, five-finger flexion angle sensors, strain gauge grip force sensors, a displacement sensor for the surface of an object held by the prosthesis, a drive for locking device 2 of the rotary base. first finger, network interfaces for wired and wireless communication with external devices, interfaces for receiving bioelectric control signals, input/output means for displaying and setting up prosthesis functions, power supply device. The device is also sized to allow installation of a bionic prosthesis inside the palm. However, the disadvantage of this system is the absence of an autonomous power supply control unit, which includes a charging subunit, a voltage control subunit and a supply voltage conversion subunit.

Essence Revealing

In recent years, in connection with the development of modern microelectronic base, it has become possible to minimize the size and weight of medical equipment, including bionic prostheses. Bionic prostheses are gradually replacing traditional ones, which do not allow a person to control the movements of artificial fingers. One of the components that influences the large dimensions and heavy weight of the prosthesis is the control equipment for the bionic prosthesis. Thus, by achieving a reduction in the overall dimensions and weight of the equipment, it is possible to improve the user characteristics of the entire product.

Consequently, the technical task was set to develop a control device for a bionic prosthesis, made in the form of a board with dimensions of no more than 70 × 40 × 10 mm, weighing no more than 20 grams and performing the following functions:

control of 6 electric motors;

receiving data from 6 electromyographic (EMG) sensors, 6 current sensors and 6 electric motor position sensors;

generation of supply voltages for operation of electric motors (+5 V) and microcontroller (+3.3 V);

control of charging of a 2S2P type battery (two cells in series, two in parallel) from a voltage source of 10 V;

protecting the battery from discharge below permissible values (3 V) and ensuring recovery from this state during subsequent charging;

active balancing with a current of up to 200 mA of series-connected battery elements;

protection against battery overheating when charging;

control of external indication of the state of the battery charging process. Red when charging is in progress, green when charging is successful, both together when the cells are overheated or damaged.

When analyzing the market for existing solutions, no single device was found that provides all the necessary functionality.

The technical result achieved by implementing the proposed utility model is to reduce the weight and size characteristics of the bionic prosthesis control system and combine all its components in one device with the addition of functions for working with a battery, which helps improve the noise immunity of the utility model.

This task is achieved due to the fact that the utility model consists of the following functional blocks: a control unit for a bionic prosthesis, the main element of which is a microcontroller that makes it possible to achieve a minimum processing time for signals from electromyographic sensors and calculate signals for controlling electric drives of a bionic prosthesis; a current sensor unit that allows you to receive force feedback to electric motors; Unlike the prototype, it is equipped with a power control unit, which is divided into functional subunits: a battery subunit, which is the power source for the autonomous operation of the bionic prosthesis, a charging subunit, which charges the battery, a voltage control subunit, which accurately measures the voltage on the 4th battery , a balancing subunit that balances the battery cells, a voltage conversion subunit that generates the supply voltage for the entire device. These blocks are electronic components installed on a printed circuit board made of heat-resistant PCB, covered with a solder mask, by soldering and electrically connected to each other by copper printed conductors.

Brief description of drawings

The essence of the utility model can be revealed in the following drawings:

Fig. 1 - structural functional diagram,

Fig. 2 - electrical circuit diagram,

Fig. 3 - general view of the utility model printed circuit board.

Implementation of a utility model

The control unit for bionic prosthesis 1 is based on the STM32F303RET6 microcontroller. The battery subunit 2 of the power control unit 3 is made in the form of 4 cells of standard size 18650, 2 of which are connected in series, 2 in parallel according to the 2S2P circuit. Together with them, an NTC thermistor is installed to control the temperature of the cells. In the voltage control subunit 2 of the power control unit 3, MCP100T-300I/TT supervisors with a current consumption of 45 μA and a measurement accuracy of ±75 mV were used. Balancing subunit 4 used an LM2663 chip with a current of up to 200 mA and a consumption of 1.3 mA. The voltage conversion subunit in the power control unit consists of voltage converters of 5 V and 3.3 V. The +5 V converter in the supply voltage conversion subunit 5 was made on an ST1S10 chip, with a current of up to 3A. The +3.3 V converter in the supply voltage conversion subunit 5 was made on the L78L33 chip with an output current of up to 100 mA.

The current sensor block 6 is made on a ZXCT1010 chip with a sensitivity of 1 mV/mA in the range of 10-3000 mA.

Charging subunit 7 is made on a BQ2057WSN chip with a voltage regulation error of 1%. To control the charging current in charging subunit 7, a p-channel transistor IRF4905 is selected.

All electronic components are installed on a printed circuit board with dimensions of 70x40x10 mm made of heat-resistant textolite FR4, covered with a solder mask, by soldering and electrically connected to each other by copper printed conductors 33 microns thick. The weight of the assembled useful model was 20 grams.

Claims (4)

1. A board for controlling a bionic prosthesis, characterized in that it consists of the following functional blocks: a control unit for a bionic prosthesis, the main element of which is a microcontroller capable of processing signals from electromyographic sensors and calculating signals for controlling electric drives of a bionic prosthesis, a block of current sensors, designed with the ability to receive feedback on the force on the electric motors, characterized in that it is equipped with a power control unit, which is divided into functional subunits: a battery subunit, which is a power source for autonomous operation of the bionic prosthesis, a charging subunit, configured to charge the battery, a subunit voltage control, configured to measure with high accuracy the voltage on the battery, a balancing subunit, configured to balance the cells of the battery, a voltage conversion subunit, configured to generate the supply voltage for the entire device, and these blocks are electronic components installed onto a printed circuit board made of heat-resistant PCB, covered with a solder mask, by soldering and electrically connected to each other by copper printed conductors. 2. A board for controlling a bionic prosthesis according to claim 1, characterized in that the charging subunit is made in the form of a separate printed circuit board with the ability to connect to the main board. 3. A board for controlling a bionic prosthesis according to claim 1, characterized in that the balancing subunit is made in the form of a separate printed circuit board with the ability to connect to the main board. 4. A board for controlling a bionic prosthesis according to claim 1, characterized in that the charging and balancing subunits are together made in the form of a separate printed circuit board with the ability to connect to the main board.