Continuum Arm Robot Stiffness via Electromagnetic Locking
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Solution Overview
Problem
Continuum arm robots suffer from low stiffness due to the number of joints, limiting their load-carrying capacity and interaction with the environment, especially in longer lengths where deflection causes navigation and position issues, restricting their use to lightweight tasks.
Innovation Solution
A system comprising ferromagnetic collars on the continuum arm robot and an external controllable electromagnetic device that attracts and locks the robot sections, increasing stiffness by reducing deflection and improving positional accuracy and load capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the robot arm is made longer to increase workspace reach, then the workspace coverage is improved, but the deflection increases causing position and navigation issues
Solution Approach 1:
The robot arm is divided into multiple modular sections that can be independently controlled. Each section has its own actuation system, allowing the arm to be segmented into controllable units rather than a single long cantilever beam. This segmentation reduces the effective length of each unactuated segment, minimizing deflection while maintaining overall reach.
Solution Approach 2:
The robot arm transitions from a static, continuously compliant structure to a dynamically controllable system. By actively actuating individual sections and using locking mechanisms, the arm can dynamically adjust its stiffness and configuration along its length, compensating for deflection in longer arms and maintaining positioning accuracy.
2Adaptability or versatility
If the number of joints is increased to improve dexterity, then the degrees of freedom are increased, but the stiffness is reduced
Solution Approach 1:
The system dynamically adjusts stiffness by locking and unlocking joints based on task requirements. When high stiffness is needed for load-bearing or precise positioning, joints are locked to create rigid segments. When dexterity is needed for navigation, joints are unlocked to allow compliant movement. This dynamic control resolves the contradiction between stiffness and adaptability.
Solution Approach 2:
The physical parameters of the robot arm, specifically the stiffness of each section, are changed on-demand through actuation and locking mechanisms. The system can transition between compliant and rigid states, allowing it to optimize between dexterity and stiffness depending on the operational phase - compliant during navigation, rigid during task execution.
3Strength
If locking mechanisms are added to increase stiffness, then the load carrying capacity is improved, but the device complexity increases
Solution Approach 1:
The locking and actuation mechanisms are extracted from the main robot arm structure and implemented as separate, modular components. This allows the stiffening function to be added independently without fundamentally redesigning the entire arm structure, reducing the complexity increase while achieving the desired load-bearing capability.
Solution Approach 2:
The patent replaces complex mechanical locking mechanisms with electromagnetic actuators and ferromagnetic locking points. This substitution simplifies the locking mechanism by using magnetic attraction forces instead of complex mechanical engagement systems, reducing device complexity while maintaining the ability to increase stiffness when needed.
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 enhances the stiffness and control of continuum arm robots, allowing them to perform more challenging tasks with improved accuracy and load capacity without increasing task duration or limiting access to confined spaces.
Implementation Method 1
at least one external controllable electromagnetic device which can be activated so that the ferromagnetic section on the continuum arm robot is attracted to the electromagnetic device
Implementation Method 2
a passive robot section through which controls for the manipulatable tip, and at least one ferromagnetic collar
Data Source
AI summary
A locking system for a continuum arm robot system, the robot system includes: a continuum arm robot having a manipulatable tip, a passive robot section through which controls for the manipulatable tip, and at least one ferromagnetic collar, and at least one external controllable electromagnetic device which can be activated so that the ferromagnetic section on the continuum arm robot is attracted to the electromagnetic device.