Patient Support Actuator Power Control Under Variable Load
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Solution Overview
Problem
Conventional actuator control systems in patient support apparatuses do not account for varying loads, leading to inconsistent movement speed and increased electrical current draw, which can result in electrical overload and circuit protection interruptions in healthcare facilities.
Innovation Solution
A controller system that adjusts the actuator's voltage and current based on the applied load, using sensors to monitor and manage the output power to maintain a desired level, preventing overload and ensuring consistent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the actuator is preconfigured to provide the same output regardless of load, then the control system is simple, but the movement speed becomes inconsistent under varying patient weights
Solution Approach 1:
The control system dynamically adjusts actuator parameters based on real-time load conditions. The controller modifies voltage, current, and movement parameters according to the actual patient weight and position, transitioning from a static preconfigured system to a dynamic adaptive system that maintains consistent movement speed across varying loads.
Solution Approach 2:
The system changes operational parameters (voltage, current, movement speed) based on detected load conditions. Sensors monitor patient weight and position, and the controller adjusts electrical and mechanical parameters in real-time to maintain optimal actuator performance across different loading scenarios.
2Force
If the actuator draws more electrical current with increases in torque, then the actuator can handle heavier loads, but the electrical system may become overloaded and trigger circuit protection
Solution Approach 1:
The system implements feedback control by monitoring electrical current draw and comparing it against safe operating thresholds. When current approaches dangerous levels, the controller receives feedback and automatically adjusts actuator operation to reduce power consumption, preventing circuit overload while maintaining necessary torque for patient safety.
Solution Approach 2:
The controller applies partial action by providing only the necessary torque and power required for current operational conditions rather than maximum capacity. This prevents excessive current draw that would trigger circuit protection while still delivering sufficient force for patient handling, using just-enough power principle.
3Speed
If the actuator operates at full power to maintain consistent speed under heavy load, then the movement speed remains consistent, but the electrical current draw increases and may cause overload
Solution Approach 1:
The system dynamically adjusts power delivery based on actual operational needs. Rather than operating at fixed full power, the controller modulates electrical input in real-time according to load conditions, maintaining consistent movement speed while optimizing energy consumption to prevent electrical overload.
4Adaptability or versatility
If the actuator is controlled to handle maximum load, then the system can accommodate heavier patients, but the device complexity increases with additional sensors and control mechanisms
Solution Approach 1:
The control system serves multiple functions: it monitors load, adjusts motor parameters, prevents overload, and maintains consistent speed all through a single integrated controller. This multi-functionality reduces the need for separate dedicated components for each function, managing complexity while achieving versatile load handling capability.
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 effectively controls actuator movement speed and electrical power consumption, preventing overloads and ensuring continuous operation of patient support apparatuses by dynamically adjusting voltage and current in response to changing loads.
Implementation Method 1
A controller system that adjusts the actuator's voltage and current based on the applied load, using sensors to monitor and manage the output power to maintain a desired level
Data Source
AI summary
Systems, methods and techniques for operating a patient support apparatus are disclosed. The patient support apparatus includes a support structure including a base and a patient support surface to support a patient. The patient support apparatus also includes an actuator coupled to the support structure and operable to move the patient support surface. The actuator is configured to receive an applied voltage and an applied electrical current, and to produce an output power, where the applied electrical current varies based on different loads applied to the actuator. A controller is coupled to the actuator to determine a desired output power of the actuator and to control the actuator such that the output power produced by the actuator is controlled relative to the desired output power by modifying the applied voltage to compensate for the different loads being applied to the actuator.