Sensored Brushless Motors for Compact Prosthetic Hand Actuation
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Solution Overview
Problem
Existing prosthetic limbs face limitations due to the size and performance of motors, which are either too weak, slow, or too large to provide sufficient power, precision, and durability for effective actuation.
Innovation Solution
A system utilizing miniaturized sensored brushless motors with Field Oriented Control (FOC) and calibrated encoders, integrated into a prosthetic assembly, enabling high precision, efficient, and powerful actuation of prosthetic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If small motors are used in prosthetic limbs, then the prosthetic limb size is reduced, but the motor power, reaction time, and durability are insufficient
Solution Approach 1:
The motor is divided into separate functional modules: stator, rotor, magnets, and encoder, allowing independent optimization of each component. This segmentation enables the motor to achieve high power density while maintaining a compact overall size suitable for prosthetic limbs.
Solution Approach 2:
The motor components are nested within each other - the rotor is positioned inside the stator, magnets are embedded in the rotor, and the encoder is integrated into the motor assembly. This nested configuration maximizes space utilization and reduces the overall motor volume while maintaining sufficient power output.
2Power
If motors with sufficient power are used, then motor power and durability are improved, but the motor size becomes too large to fit in prosthetic limbs
Solution Approach 1:
The motor design employs optimized parameters including magnet strength, winding configuration, and magnetic circuit geometry to achieve high power density. By carefully selecting and optimizing these parameters, the motor delivers sufficient power while maintaining a compact size that fits within prosthetic limb constraints.
Solution Approach 2:
The motor utilizes composite construction with magnetic materials, conductive windings, and structural components integrated into a unified design. This composite approach allows the motor to achieve high strength-to-weight ratio and high power density, providing sufficient power in a reduced volume suitable for prosthetic applications.
3Measurement precision
If precise motor control is implemented, then motion precision is improved, but the device complexity increases
Solution Approach 1:
An encoder is integrated into the motor assembly to provide real-time feedback on rotor position and speed. This feedback mechanism enables precise control of prosthetic limb motion through closed-loop control, while the encoder is compactly integrated to minimize additional complexity in the overall system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides enhanced grip strength, reduced noise, faster motion, lower power consumption, extended battery life, and increased longevity of prosthetic limbs, allowing for complex object manipulation and improved user experience.
Implementation Method 1
brushless motors... enabling high precision, efficient, and powerful actuation
Implementation Method 2
calibrated encoders... enabling high precision... actuation
Data Source
AI summary
A system and method for a prosthetic assembly that includes a first prosthetic component, comprising a prosthetic hand base; a set of second prosthetic components, comprising a set of prosthetic fingers, and a set of actuating systems, wherein one actuating system connects a pair of distinct prosthetic components, enabling actuation of one prosthetic component with respect to the other. Each actuating system, from the set of actuating systems, includes a linkage and a sensored brushless motor; wherein the sensored brushless motor comprises a brushless motor, a field oriented control system, a rotary encoder, and a gearbox.