Handle Assembly Position Sensor for Patient Transport Drive Control

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Solution Overview

Problem

Traditional patient transport systems rely on expensive force sensors to determine the speed of the drive system, which can be underutilized and may provide inaccurate readings, leading to inefficiencies and inaccuracies in patient movement.

Innovation Solution

A patient transport apparatus equipped with a handle assembly featuring position sensors, such as accelerometers and gyroscopes, that control a drive system with motors to propel the apparatus forward or backward based on the handle's position and inclination, reducing the need for force sensors and enhancing movement efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If force sensors (load cells) are used to determine drive system speed, then measurement accuracy is improved, but device cost and complexity increase

Engineering Contradiction:

Improveforce measurement accuracyVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical force sensors (load cells) with an electronic sensor system comprising accelerometers and gyroscopes mounted on the handle assembly. This substitution uses electronic inertial measurement to infer drive system speed and direction, eliminating the need for mechanical force measurement components and their associated complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary computational system that processes signals from accelerometers and gyroscopes to determine drive system velocity. This intermediary layer translates inertial measurements into speed control data, providing accurate measurement without direct force sensing, thereby reducing device complexity while maintaining precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If force sensors are used to control drive system speed, then speed control accuracy is improved, but ease of operation deteriorates due to caregiver effort

Engineering Contradiction:

Improvespeed control accuracyVSAvoidcaregiver physical effort

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements a feedback control system where accelerometers and gyroscopes continuously monitor the handle assembly's motion, and the controller adjusts drive system speed based on this feedback. This closed-loop system maintains accurate speed control while requiring minimal physical effort from the caregiver, as the system actively compensates for applied forces.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The drive system performs self-service by using its own motion-induced inertial forces (detected by accelerometers and gyroscopes) to control its speed. The system essentially measures its own movement characteristics and uses this information for automatic speed regulation, eliminating the need for the caregiver to exert additional effort for control.

Inventive Principle:

Principle #25Self-service

3Device complexity

If traditional handle assemblies are used, then device simplicity is maintained, but measurement accuracy and control precision deteriorate

Engineering Contradiction:

Improvehandle assembly simplicityVSAvoidposition and inclination detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent makes the handle assembly multi-functional by integrating not only manual gripping functionality but also mounting for accelerometers and gyroscopes. The same handle structure serves both as a user interface and as a platform for precision sensing, achieving accurate position and inclination detection without significantly increasing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution allows for efficient and accurate patient transport by reducing the caregiver's effort required to move the apparatus, providing precise control over the direction and speed of movement, and eliminating the need for costly force sensors, thus improving the overall operational efficiency and accuracy.

Implementation Method 1

the handle assembly comprises a position sensor, such as an accelerometer

Methodology Applied

Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

position sensors, such as accelerometers and gyroscopes

Methodology Applied

Scientific EffectGyroscope: Gyroscope

Data Source

PatentUS11642262B2Patient transport apparatus with handle assembly for controlling drive system

Publication Date: 2023.05.09 STRYKER CORP

AI summary

A patient transport apparatus transports a patient over a surface. The patient transport apparatus comprises a support structure comprising a base, a patient support surface, and a reference sensor arranged to sense inclination of the support structure. A drive system is coupled to the support structure and operable to propel the patient transport apparatus. A handle assembly is operable by a user to control operation of the drive system. The handle assembly comprises a handle movable relative to the base and a position sensor arranged to sense positioning of the handle. A controller is coupled to the reference sensor and the position sensor, and is adapted to control the drive system in response to signals received from the reference sensor and the position sensor.