4D Theater Chair Drive Layout for Low Vibration Motion

The patent applies asymmetry by installing actuators at specific angles (α and -α) relative to the horizontal centerline rather than in parallel. This asymmetric angular arrangement creates a geometric configuration where the Y-axis force components generate equal and opposite moments about the spline device, causing the moments to cancel each other out. This resolves the technical contradiction by eliminating the harmful Y-axis force moments while maintaining structural simplicity through the symmetric angular pattern.

The patent implements a counterbalancing mechanism where the two actuators positioned at angles α and -α create opposing moments that counterweight each other. The Y-axis force component from one actuator produces a moment in one direction, while the other actuator produces an equal moment in the opposite direction, effectively neutralizing the net moment about the spline device and eliminating the associated vibration and noise.

The patent uses asymmetric angular installation (α and -α) to minimize load disturbance while controlling complexity. The specific angular configuration creates a geometric relationship where force components are optimized to reduce moments about the spline device. The complexity is managed by using a symmetric angular pattern that simplifies the overall design process and allows for standardized mounting procedures.

The patent applies parameter changes by optimizing the angular parameter (α) of actuator installation. By selecting specific angle values, the design achieves minimal load disturbance and moment generation. This parameter optimization balances the trade-off between performance (reduced load disturbance) and complexity (installation requirements), as the angular parameter can be selected based on geometric relationships that simplify manufacturing and assembly.

The patent employs spherical joints (universal joints) at the actuator-plate coupling points. These spherical connections allow motion in multiple directions while distributing loads more evenly across the joint surfaces. The curved geometry of spherical joints reduces stress concentration compared to rigid hinges, minimizing bending moments and torsion loads, thereby improving the durability and reliability of the coupled portions while maintaining the necessary motion freedom.

The patent changes the coupling mechanism from rigid hinged connections to spherical joints, altering the mechanical parameters of the connection. This parameter change allows for greater motion freedom while distributing forces more favorably, reducing the bending moments and torsion loads that would otherwise concentrate at rigid hinge points. The spherical joint design inherently handles multi-axis motion while reducing stress on the coupled portions.