Aircraft Joystick Cardan Joint Decoupling for Stationary Shaft Mounting
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Solution Overview
Problem
Existing aircraft control devices with multi-axis tiltable control sticks face complexity in design and installation due to the need for movable components and intricate cable routing, especially when simulating control feel with active stick controls, which complicates the integration and conversion of sensors and actuators.
Innovation Solution
The control device introduces an additional degree of freedom to the cardan joint connection between the control stick and control shafts, decoupling roll and pitch movements, allowing the control shafts to be stationary with servomotors mounted in a housing, simplifying sensor and actuator installation and enabling modular use by allowing fixed mounting of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a classic cardan joint is used to connect the control stick with two control shafts, then the control stick can be tilted in two axes (pitch and roll), but the control shafts become movable requiring complex cable routing and increasing device complexity
Solution Approach 1:
The cardan joint is segmented into a fixed portion (mounted on the housing) and a movable portion (the control stick). By fixing the joint to the housing rather than allowing it to move with the control shafts, the patent separates the tilting function from the shaft movement, enabling simple cable routing while maintaining two-axis control capability
Solution Approach 2:
Instead of mounting the cardan joint on the movable control shafts (conventional approach), the patent inverts the mounting approach by fixing the joint to the stationary housing. This inversion allows the control shafts to remain stationary while the control stick provides two-axis tilting through the fixed joint, eliminating the need for complex movable cable routing
2Ease of operation
If control shafts are made movable to enable two-axis control stick tilting, then pitch and roll control is achieved, but the assembly and installation of control components becomes more difficult
Solution Approach 1:
The patent inverts the conventional mounting approach by making the control shafts stationary and mounting the cardan joint to the fixed housing. This allows control components to be assembled on stationary shafts, greatly simplifying installation and manufacturing while maintaining full two-axis control functionality through the fixed joint mechanism
3Reliability
If active stick controls with servomotors are implemented to simulate control feel, then control feedback is improved, but the device complexity and number of components increases
Solution Approach 1:
By making the control shafts stationary and mounting them directly to the housing, the patent creates a stable platform for mounting servomotors and other control components. This inverted mounting approach reduces the number of moving connections required, simplifies the overall component architecture, while still enabling active stick control with feedback mechanisms
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
This design simplifies assembly, reduces moving masses, enhances reliability, and facilitates modular conversion of control designs, achieving a simpler and more reliable control device with reduced complexity and increased flexibility for both active and passive control configurations.
Implementation Method 1
the control stick (7) with its cardan-like joint (8) for articulation on the two control shafts (3, 4) has an additional degree of freedom compared to a classic cardan joint, which decouples the control stick (7) from the control shafts (3, 4) with respect to pitch movements for roll movements and from the control shafts (3, 4) with respect to roll movements for pitch movements
Data Source
Figure 1
AI summary
The device has a control stick (7) tiltable about multiple axes for actuating at least two control signal senders for pitch and roll control of the aircraft, two control shafts (3,4) connected to the control stick via a gimbal joint (8) for converting pitch and roll movements of the stick into shaft rotations. The two control shafts are rotatably mounted in a fixed position on a common frame (2) and the joint has a free-running device for each control shaft for tilting of the control stick in a plane parallel to the respective control shaft.