Clutched Robotic Joint Module With Quasi-Passive Elastic Actuation
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Solution Overview
Problem
Robotic systems face challenges in minimizing power consumption while maintaining adequate force output, often requiring a trade-off between power and efficiency, with high-power systems being costly and inefficient systems lacking practicality for human-assisted tasks.
Innovation Solution
A clutched joint module with a quasi-passive elastic actuator that combines primary torque from an electric motor with augmented torque from a torsional coil spring, allowing the system to operate in both elastic and inelastic states to optimize energy use, reducing power consumption and enhancing force output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high-output power systems are employed to meet force output demands, then force output capability is improved, but power consumption increases and efficiency deteriorates
Solution Approach 1:
The system dynamically switches between two operational modes using a clutch mechanism: an elastic mode where the spring actuator stores and releases energy passively, and an inelastic mode where both actuators work together. This dynamic reconfiguration allows the system to adapt its power consumption and force output characteristics to match task requirements, resolving the contradiction between high force output and low power consumption
Solution Approach 2:
The system changes the mechanical parameter of the spring actuator from an elastic state (storing energy) to an inelastic state (dissipating energy or providing direct force) through the clutch mechanism. This parameter change allows the same component to serve different functional roles, enabling high force output when needed while maintaining low power consumption during passive operation
2Use of energy by moving object
If efficient power systems are employed to improve energy efficiency, then power consumption is reduced, but force output capability deteriorates
Solution Approach 1:
The system merges two actuator types with complementary characteristics: a spring actuator for efficient passive operation and an electric motor for high-force active operation. The clutch mechanism enables these two actuators to work together in the inelastic mode, combining their force outputs to achieve high force capability while maintaining overall system efficiency through intelligent coordination
3Force
If high-power actuators are used to ensure adequate force output, then force capability is improved, but system weight and complexity increase
Solution Approach 1:
The actuation system is segmented into two separate actuators with distinct functions: a spring actuator for passive/efficient operation and an electric motor for active/high-force operation. This segmentation allows each component to be optimized for its specific role, reducing the need for an oversized single actuator and thereby reducing overall system complexity and weight
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 enables robotic systems to achieve significant power savings while maintaining or improving force output, allowing for more efficient operation and reduced weight and complexity, particularly in exoskeletons and humanoid robots.
Implementation Method 1
a quasi-passive elastic actuator that combines primary torque from an electric motor with augmented torque from a torsional coil spring
Implementation Method 2
augmented torque from a torsional coil spring
Data Source
AI summary
A method for operating a robotic joint of a robotic system comprising selectively operating a clutch mechanism of a clutched joint module in an engaged state to cause a quasi-passive elastic actuator to enter an elastic state, the clutched joint module operating about and defining a joint of the robotic system. The method comprising effecting a first rotation of the joint to cause the quasi-passive elastic actuator to store energy during at least a portion of the rotation of the joint. The method comprising effecting a second rotation of the joint and causing the stored energy from the quasi-passive elastic actuator to be released in the form of an augmented torque applied to an output member of the clutched joint module. The method comprising selectively operating the clutch mechanism in a disengaged state to cause the quasi-passive elastic actuator to enter an inelastic state. The method comprising effecting a third rotation of the joint, wherein the quasi-passive elastic actuator facilitates a free swing mode of the clutched joint module and the joint.