Flapping Robot Blade Drive With Torsion Spring Resonance Control
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Solution Overview
Problem
Existing flapping devices face challenges in achieving a high power-to-weight ratio, compact size, and cost-effectiveness, particularly when using outrunner-type motors, which require higher motor power to resist the restoring force of large springs, leading to increased size and complexity.
Innovation Solution
A flapping device design incorporating a pair of blades with drive units featuring a drive source, a driven part, a first vibration excitation member, and a control unit, utilizing outrunner motors and torsion springs to amplify flapping frequency and stabilize control, with one end of the vibration excitation member being a free end to offset amplitude center without resisting restoring force, and employing offset control and feedback mechanisms to maintain precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an outrunner-type motor is used to increase power-to-weight ratio, then cost and power-to-weight ratio are improved, but motor power must be increased to resist the restoring force of large springs, leading to increased size and complexity
Solution Approach 1:
The patent applies mechanical vibration by utilizing the natural flapping frequency of the blades and employing a torsion spring to provide restoring force. The system is designed to operate near the natural frequency of the blade-spring system, allowing efficient flapping motion without requiring excessive motor power. The torsion spring constant and blade inertia are carefully balanced to achieve resonance-like conditions that amplify flapping frequency while keeping motor requirements manageable.
Solution Approach 2:
The patent changes key parameters including the torsion spring constant (K), blade rotational inertia (I), and motor characteristics to optimize system performance. By adjusting these parameters, the system achieves a balance where the flapping frequency is sufficiently high for compact size while the motor power requirement remains reasonable. The design allows tuning of the K/I ratio to match motor capabilities and achieve desired flapping frequencies.
2Speed
If the spring constant K is increased to increase rotational inertia I, then flapping frequency is improved, but the size of the spring is increased to increase the mass
Solution Approach 1:
The patent employs parameter changes by optimizing the torsion spring constant and blade inertia values to achieve the desired flapping frequency without excessive spring mass. The design seeks an optimal balance point where the spring is sufficiently stiff to provide necessary restoring force but not so massive that it defeats the purpose of a compact, high-frequency system.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and pre-configuring the optimal spring constant and blade inertia values during the design phase. This allows the system to achieve the target flapping frequency from the outset without requiring iterative adjustments or oversized components, thereby minimizing spring mass while maintaining adequate flapping frequency.
3Adaptability or versatility
If a compact flapping device is designed for toys and confined spaces, then adaptability is improved, but sufficient lift force becomes difficult to acquire due to limited blade length
Solution Approach 1:
The patent applies mechanical vibration by operating the flapping blades at high frequencies near their natural frequency. This high-frequency flapping motion generates sufficient lift force from compact blade dimensions, enabling the device to achieve adequate lifting capability while maintaining a small size suitable for toys and confined space operations.
Solution Approach 2:
The patent applies preliminary anti-action by using the torsion spring to provide a pre-configured restoring force that works in opposition to the aerodynamic loads on the blades. This pre-established elastic restoring force helps maintain stable high-frequency flapping motion, ensuring sufficient lift generation from compact blades without requiring excessive motor power or blade size.
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 design achieves a low-cost, compact flapping device with improved power-to-weight ratio, stable control, and efficient energy use, enabling high-precision flight in various directions and efficient lift force generation.
Implementation Method 1
a first vibration excitation member (40) that applies a biasing force to the driven part (10) in a direction opposite to a rotation direction of the driven part (10) in accordance with rotation of the driven part (10)
Implementation Method 2
an outrunner-type brushless DC motor having a high power-to-weight ratio
Implementation Method 3
flapping devices have been used for surveillance, photographing, various inspections, and the like from above
Data Source
AI summary
[Problem] To provide a flapping flying robot that is compact and is capable of performing flight with high mobility.[Solution] A flapping device 1 has blades 2, 2 and a drive unit 3, and the drive unit 3 includes: a drive source 30; a driven part 10 rotated around a first rotation axial line by the drive source 30; a first vibration excitation member 40 biasing the driven part 10 in a direction opposite to a rotation direction of the driven part 10; and a control unit 60. The blade 2 has: a first blade shaft 20 extending in a predetermined axial line direction and being connected to the driven part 10 on a one end side and connected to be rotatable in a second rotation axial line surrounding direction intersecting the first rotation axial line; a second blade shaft 21 extending in a direction intersecting the first blade shaft 20 and being directly or indirectly connected to the driven part 10 on a one end side and connected to be rotatable in the first rotation axial line surrounding direction; and a blade main body 22 disposed over the first blade shaft 20 and the second blade shaft 21.