Exercise Device Limb Interface Gimbal Lock Prevention

The patent implements dynamic rotation limits that adapt based on the current orientation of the handle. As the handle approaches orientations that would cause gimbal lock, the rotation limits dynamically adjust to prevent the singular configuration, while still allowing full range of motion in safe orientations. This is achieved through controllers that monitor joint angles and adjust soft limits in real-time.

The patent introduces intermediate computational layers (controllers and software algorithms) that mediate between the user's input forces and the mechanical joints. These intermediaries calculate optimal rotation limits based on current orientation, preventing gimbal lock without restricting natural movement patterns. The intermediary system translates complex multi-axis motion requirements into safe, constrained joint movements.

The patent employs dynamic rotation limits that change in real-time based on the handle's orientation. Rather than imposing fixed, conservative limits that restrict natural movement, the system continuously adjusts the allowable rotation range to maximize freedom of motion while preventing gimbal lock only when necessary. This creates an invisible constraint system that feels natural to the user.

The system dynamically changes the parameters (rotation limits) based on the operational state (joint angles and orientation). When the handle is in safe orientations, full rotation is permitted. When approaching dangerous orientations, the parameters are adjusted to prevent gimbal lock. This parameter adaptation occurs seamlessly, maintaining movement naturalness.

The patent makes the control system universal by implementing a single software-based solution that handles all rotation limit calculations for multiple joints. Rather than requiring separate mechanical constraint mechanisms for each joint, a universal controller algorithm manages all joints, reducing mechanical complexity while maintaining full three-dimensional motion capability.

The patent replaces complex mechanical constraint systems with software-based control. Instead of using additional mechanical stops, springs, or physical constraints to prevent gimbal lock, the system uses computational algorithms to monitor and limit joint rotations. This substitution dramatically reduces device complexity while maintaining the same functional benefits.