Articulation with Controllable Stiffness and Integrated Force Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing locomotion devices such as prostheses, orthoses, exoskeletons, and walking robots face challenges in replicating the dynamic stiffness and adaptability of human articulations, leading to inefficiencies and increased energy consumption due to fixed stiffness mechanisms and bulky designs with external torque sensors.
Innovation Solution
An articulation system with controllable stiffness and integrated force measurement, utilizing a first device for position adjustment and a second device with a resistive element and motor to regulate stiffness, where the resistive element's pre-compression is measured through a rotational and linear displacement system, allowing for independent control of position and stiffness without increasing the overall volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external torque sensors are incorporated between the actuator and the load to measure force/torque in the articulation, then measurement precision is improved, but the volume of the articulation increases considerably
Solution Approach 1:
The patent combines the force measurement function with the existing actuator structure by using the resistive element (spring) that is already part of the variable stiffness mechanism. The force sensor is integrated into the actuator assembly rather than being an external component, merging multiple functions (stiffness control and force measurement) into a single compact unit.
Solution Approach 2:
The resistive element serves dual purposes: it provides the elastic force necessary for variable stiffness control and simultaneously acts as the measurement element for force/torque sensing. This multi-functional approach eliminates the need for separate external torque sensors, reducing overall system volume while maintaining measurement capability.
2Adaptability or versatility
If two motors are used to independently control position and stiffness of the articulation, then adaptability is improved, but device complexity increases
Solution Approach 1:
The control system is segmented into two independent control loops: one for position control and another for stiffness control. Each control loop manages specific parameters, allowing independent adjustment without requiring a completely new actuator design. This modular control approach reduces complexity compared to a fully integrated single-control system.
Solution Approach 2:
The articulation employs a dynamically adjustable stiffness mechanism using a resistive element (spring) that can be actively controlled to vary its mechanical properties in real-time. This dynamic adjustment capability allows the system to adapt to different operational conditions while maintaining a relatively simple mechanical structure.
3Device complexity
If fixed stiffness mechanisms are used in locomotion devices, then device complexity is reduced, but energy efficiency deteriorates due to inability to adapt to different environments
Solution Approach 1:
The system changes the stiffness parameter of the articulation dynamically based on operational requirements. By adjusting the pre-compression of the resistive element, the articulation can optimize its mechanical properties for different tasks and environmental conditions, improving energy efficiency without requiring a completely complex reconfigurable structure.
Solution Approach 2:
The resistive element is pre-compressed to a specific level before operation, establishing an initial stiffness state. This preliminary action allows the system to start in an energetically optimal configuration and then make incremental adjustments as needed, reducing the energy required for continuous stiffness modulation.
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 enables efficient energy use and compact design by allowing adaptive stiffness and force measurement within the articulation, reducing energy consumption and minimizing volume, while eliminating the need for external torque sensors.
Implementation Method 1
many designs and research are being oriented to the development of motorised articulations, which are capable of adapting to obstacles of an unknown environment and have energy storage capacity to reduce the energy efforts of locomotion
Implementation Method 2
a first device (20) which performs the adjustment of the position of the articulation (1), this first device (20) comprising a frame (4) connected to a first motor element (2)
Implementation Method 3
a second device (22) which performs the regulation of the stiffness of the articulation (1), this second device (22) also serving as anchorage of the first device (20) to the articulation (1)
Data Source
AI summary
The subject matter of the invention is an articulation (1) with controllable stiffness and a force-measuring system, comprising a first device (20) that comprises a frame (4) having a curved face and connected to a first motor element (2), the first device (20) regulating the position of the articulation (1), and a second device (22) that regulates the stiffness of the articulation (1) and comprises a thrust element (15), the movement (D) of which determines the pre-compression of a resistive element (11) and thus the stiffness of the articulation (1); the first motor element (2) causes the frame (4) to rotate such that a wheel (8) of the second device (22) rolls on the curved face of the frame (4), causing the resistive element (11) to be compressed (C) via a transmission rod (7) associated with the wheel (8) and with the resistive element (11).