Flexible Robotic Actuator With Patterned Bending Limit for Safe Grasping
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Solution Overview
Problem
Existing robotic devices for upper limb rehabilitation are bulky, cumbersome, and pose safety risks due to powerful electric motors, making them unsuitable for use outside laboratory settings, and lack effective control methods for grasping objects during daily activities.
Innovation Solution
A flexible robotic actuator using a soft body with patterned sections and pressurized fluid chambers to provide lightweight, portable assistance, combined with a control system for controlled bending and extension, and a muscle stimulator for enhanced muscle strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If powerful electric motors and rigid metal frameworks are used in robotic devices, then the devices can provide sufficient force for rehabilitation, but the devices become bulky and heavy
Solution Approach 1:
The patent employs pneumatic artificial muscles (PAMs) as actuators instead of traditional electric motors. These PAMs use pressurized air to generate force through pneumatic pressure, enabling the robotic device to provide sufficient rehabilitation force while maintaining a lightweight and compact structure. The pneumatic actuation system eliminates the need for heavy motors and rigid metal frameworks.
Solution Approach 2:
The robotic device utilizes flexible materials and soft structures throughout its construction. The robotic finger incorporates flexible joints, soft gripper elements, and compliant mechanisms that replace rigid metal components. This flexible construction significantly reduces weight while maintaining the necessary force transmission capabilities through pneumatic actuation.
2Reliability
If robotic devices are designed for laboratory settings with tethered power sources, then they can provide controlled assistance, but they become cumbersome and unattractive for use outside the clinic
Solution Approach 1:
The robotic device is designed with a self-contained, multi-functional architecture that integrates pneumatic power generation, control electronics, and sensing capabilities into a single portable unit. The device can operate independently without external tethers, providing both reliable control and portability for use in diverse settings including home environments.
Solution Approach 2:
The device incorporates onboard pneumatic pumps and control systems that enable it to self-regulate its operation. The integrated sensor suite provides real-time feedback for autonomous control, eliminating the need for external power sources and complex tethered connections, thereby achieving both reliability and portability.
3Force
If rigid metal frameworks and powerful motors are used, then the devices can assist movement, but they may pose dangers to patients due to over-powered operation
Solution Approach 1:
The robotic device is constructed entirely from flexible and soft materials, including flexible joints, soft gripper elements, and compliant structural components. This soft construction inherently limits the maximum force that can be exerted on the patient, preventing over-powered operation while still providing sufficient assistance for rehabilitation tasks.
Solution Approach 2:
The device incorporates compliant mechanisms and flexible structures that dynamically adapt to patient movement. The soft materials and flexible joints allow the device to yield to patient-initiated movements, providing assistance only when needed and automatically reducing force when the patient attempts to move independently, thereby enhancing safety.
4Force
If traditional robotic structures are used, then the devices can provide mechanical assistance, but they lack effective control methods for grasping objects during daily activities
Solution Approach 1:
The robotic device incorporates an integrated sensor suite including force sensors, position sensors, and tactile sensors that provide real-time feedback to the control system. This feedback enables precise control of the soft gripper's grasping force and position, allowing the device to effectively manipulate objects during daily activities while maintaining safe and natural interaction.
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 flexible robotic actuator offers safe, compact, and effective rehabilitation by mimicking natural movements, providing controlled flexion and extension, and assisting in grasping tasks with minimal harm to the user.
Implementation Method 1
The at least one chamber is defined by the soft body and operatively driven by a pressurized fluid such that the soft body bends towards the patterned section
Data Source
AI summary
One embodiment provides a flexible robotic actuator for assisting a body part of a subject. The flexible robotic actuator comprises a soft body and at least one chamber. The soft body has a first side and a second side opposite the first side, and includes a patterned section on the first side. The at least one chamber is defined by the soft body and operatively driven by a pressurized fluid such that the soft body bends towards the patterned section and the bending angle of the soft body is limited by the patterned section.