Orthoplanar Spring Compliant Sensor for Robotic Stability
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Solution Overview
Problem
Existing robotics systems face challenges in achieving stable and accurate compliant motion during tasks that require contact with the environment, as active compliance is prone to stability issues and excessive passive compliance compromises positioning accuracy and bandwidth.
Innovation Solution
The development of compliant force/torque sensors that combine active and passive compliance, utilizing an orthoplanar spring with Hall-effect sensors and magnets to measure deformation and calculate applied forces and torques, enabling simultaneous use of both compliance methods for improved stability and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If active compliance is used to achieve compliant motion, then versatility is improved, but stability deteriorates
Solution Approach 1:
The patent combines active compliance (force control) with passive compliance (elastic elements) in a hybrid system. The robotic manipulator incorporates both active force control mechanisms and passive elastic elements (springs, flexures) to achieve compliant motion. This merging allows the system to benefit from the versatility of active control while the passive elements provide inherent stability and damping, resolving the contradiction between versatility and stability.
2Stability of the object's composition
If excessive passive compliance is used to achieve compliant motion, then stability is improved, but positioning accuracy deteriorates
Solution Approach 1:
The patent applies passive compliance selectively at specific locations where contact with the environment is required, rather than throughout the entire manipulator. The elastic elements are positioned locally at the end effector or contact points to provide compliance only where needed for stable interaction, while the rest of the manipulator maintains high stiffness for accurate positioning. This localized application resolves the contradiction between stability and positioning accuracy.
3Stability of the object's composition
If excessive passive compliance is used to achieve compliant motion, then stability is improved, but bandwidth deteriorates
Solution Approach 1:
The patent uses adjustable and tunable elastic elements with varying stiffness parameters to optimize the balance between stability and bandwidth. The passive compliance parameters (spring constants, flexure geometries) can be adjusted to match the specific application requirements, allowing the system to achieve stability when needed while maintaining high bandwidth for dynamic tasks. This parameter tuning capability resolves the contradiction between stability and bandwidth.
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 stability and responsiveness of robotic systems by allowing increased control gains without instability, improving positioning accuracy and bandwidth, and effectively managing joint and structural flexibilities.
Implementation Method 1
The sensors further comprise sensor elements that enable measurement of deformation of the orthoplanar spring relative to the support member... In some embodiments, the sensor elements comprise one or more magnets mounted to the orthoplanar spring and one or more Hall-effect sensors mounted to the support member in proximity to the one or more magnets.
Data Source
AI summary
In one embodiment, a compliant force/torque sensor includes an orthoplanar spring including a central platform and multiple legs that extend out from the platform, a support member configured to support the orthoplanar spring, wherein the legs of the orthoplanar spring are mounted to the support member in a manner in which the central platform of the orthoplanar spring can move relative to the support member, and sensor elements configured to sense movement of the central platform of the orthoplanar spring relative to the support member.